ASME Conference Presenter Attendance Policy and Archival Proceedings

2017;():V001T00A001. doi:10.1115/JRC2017-NS.

This online compilation of papers from the 2017 Joint Rail Conference (JRC2017) represents the archival version of the Conference Proceedings. According to ASME’s conference presenter attendance policy, if a paper is not presented at the Conference by an author of the paper, the paper will not be published in the official archival Proceedings, which are registered with the Library of Congress and are submitted for abstracting and indexing. The paper also will not be published in The ASME Digital Collection and may not be cited as a published paper.

Commentary by Dr. Valentin Fuster

Railroad Infrastructure Engineering

2017;():V001T01A001. doi:10.1115/JRC2017-2215.

Railroad ballast as a layer of track substructure performs important tasks such as increasing the bearing capacity of the sleepers, providing large voids for drainage and resisting the forces applied to the super-structure. Contamination of ballast as the result of ballast breakdown known as breakdown fouling can prevent ballast from performing its job and also affects the engineering properties of ballast. This paper discusses the drained static triaxial testing on granite ballast material with different amount of breakdown fouling and water content. Large-scale triaxial equipment was used for this testing program at the University of Massachusetts, Amherst. These tests were performed to study the effect of fouling and water content, on the strength properties and degradation characteristics of railroad ballasted track. Ballast with three different fouling percentages from clean to highly fouled ballast (<5%, 15% and 30%) and four water contents from dry to field capacity were tested under three different confining pressures. The results show that although an increase in moisture degrades the fouled ballast, increase in breakdown fouling at constant moisture conditions increases the strength of the ballast.

Topics: Water
Commentary by Dr. Valentin Fuster
2017;():V001T01A002. doi:10.1115/JRC2017-2218.

A railroad ballast or subballast layer is composed of unbound granular particles. The ballast/subballast initial compaction phase occurs immediately the construction or maintenance of a track structure is finished. The particles are densified into a more compact state after certain load repetitions. Geogrids are commonly used in railroad construction for reinforcement and stabilization. Currently heavy haul trains are increasing the loads experienced by the substructural layers, which changes behavior of reinforced granular particles. This paper presents a series of ballast box tests to investigate the behavior of geogrid-reinforced unbound granular particles with rectangular (BX) and triangular (TX) shaped geogrids during the compaction phase. Three types of tests were conducted: one without geogrid as a control, one with a sheet of rectangular shaped geogrid, and the other one with a sheet of triangular shaped geogrid. The geogrid was placed at the interface between subballast and subgrade layers. A half section of a railroad track structure consisting of two crossties, a rail, ballast, subballast and subgrade was constructed in a ballast box. Four wireless devices - “SmartRocks”, embedded underneath the rail seat and underneath the shoulder at the interface of ballast-subballast, and subballast-subgrade layers, respectively, to monitor particle movement under cyclic loading. The behavior of the unbound aggregates in the three sections under two different loading configurations were compared. The results indicated that the inclusion of the geogrid significantly decreased accumulated vertical displacement on the ballast surface, ballast particle translation and rotation under a given repeated loading configuration. The results also demonstrated the effectiveness of the SmartRock device and its potential for monitoring behavior of ballast particles in the field.

Commentary by Dr. Valentin Fuster
2017;():V001T01A003. doi:10.1115/JRC2017-2219.

It has been desirable for years to develop a reasonably simple, direct, accurate, and reliable method to measure pressure distributions in railroad trackbeds, especially the pressure magnitudes and distributions at the tie-ballast interface. In this study, specially-designed granular material pressure cells were used to measure pressure magnitudes and distributions. The cells were placed directly under the rail-tie intersection at the tie-ballast interface.

Initially, a MTS test machine was used to conduct a series of laboratory tie-ballast box tests for a wide variation of ballast types and loading configurations. The adequacy of the cells for in-track measurements was verified with a series of very controlled laboratory tests and measurements using simulated trackbed sections and loading conditions. Excellent correlations were obtained comparing applied machine pressures and measured transferred cell pressures indicating that this type of pressure cell is suitable for in-track tie-ballast pressure measurements. This preliminary testing sequence is briefly described.

A series of in-track wood tie tests were conducted on a yard lead track on a shortline railroad, Transkentucky Transportation, to optimize the in-track installation procedures and to obtain pressure measurements using repeated passes of low-speed locomotives and cars. A normalized pressure distribution was obtained by using metal shims when necessary to fill voids between the ties and pressure cells to insure continuous tie-ballast contact. This test sequence is presented and described.

Additional in-track tests were conducted on Norfolk Southern Railway’s heavy tonnage concrete tie Class 4 mainline with train speeds of up to 64 km/h. Data was obtained for numerous passages of revenue trains over a period of several months for variable weights and types of locomotives and freight cars at typical train speeds. The average pressure intensities at the tie-ballast interface were acquired for six consecutive ties comprising a complete revolution of the wheels. This data is presented and the results discussed.

Commentary by Dr. Valentin Fuster
2017;():V001T01A004. doi:10.1115/JRC2017-2226.

Broken rail is the most common type of mainline derailment cause on freight railroads in the United States. Detection and removal of rail defects is important for reducing the risk due to broken-rail-caused derailments. The current practice is to periodically inspect rails using non-destructive technologies, particularly ultrasonic inspection. Determining and prioritizing the frequency of rail defect inspection is an important decision in broken rail risk management. A generalized, risk-based mixed integer nonlinear programming (MINLP) model is developed which can optimize segment-specific rail defect inspection frequency to minimize route broken rail risk, especially under limited inspection resources. A numerical example to optimize the inspection frequency is used to illustrate the application of the model. The result analysis states that the optimization approach can lead to a risk reduction of broken rail compared to an empirical heuristic that all segments on the same route are tested at an equal frequency. A computer-aided decision making tool called “Rail Risk Optimizer” can be developed and implemented based on this risk-based optimization algorithm that automatically recommend an optimal segment-specific inspection scheduling. The tool will consider the risk factors such as rail age and annual traffic density to determine the segment-specific risk level. The research methodology and the practice-ready optimization tool can aid the railroad industry to mitigate broken rail risk in a cost-efficient manner.

Commentary by Dr. Valentin Fuster
2017;():V001T01A005. doi:10.1115/JRC2017-2253.

One of the key issues facing rail maintenance crews today is the successful identification and removal of rail corrugations (a sinusoidal, longitudinal rail surface deformation). Typically, rail corrugations are identified through visual inspection (which look for regular surface patterns) or audio methods (which listen for high frequency noise). Once identified, removal is accomplished through rail grinding and consists of running standard “peak-and-plow” grind pattern(s), whereby the corners of the rail are angled upwards to peak the rail, then the top of the rail is ground down (plowed) by placing numerous stones around the top of the rail. “Peak-and-plow” corrugation removal can require multiple passes depending upon the depth of the measured corrugation as well as the type of grinder (available horsepower) and the number of stones present on the grinder being utilized. The above methodology is typically applied whenever corrugation removal is required and since the grind patterns are static, significant extraneous metal removal can occur both during corrugation removal and during rail profiling.

An integrated system has been developed to identify and aid in the removal of rail corrugations. To assist in the detection and understanding of the severity of corrugations in the rail, a bogie frame mounted, accelerometer based measurement system was developed. The measured accelerations are filtered and transformed into displacement measurements which can be further processed to understand the primary wavelength and amplitude of the corrugations. These values can then be fed into specialized grinder control software which makes decisions on how to proceed with grinding; be it to remove corrugations then establish profile, only reestablish profile, or do nothing. Note that grinding may still be required to repair the rail surface due to other deformation such as rolling contact fatigue, shelling, spalling, etc. If corrugation removal grinding is required, the specialized software will create (in real-time) dynamic “peak-and-plow” grind patterns utilizing calibrated metal removal equations which estimate the amount of material one grinding stone can remove, based on the instantaneous radius of the rail, grinding motor horsepower, grinder speed, etc. The site specific, dynamic corrugation removal pattern contains calculated motor powers and orientations (angles) which will remove metal from the rails in such a way to both minimize metal removal required to eliminate the corrugations and minimize metal removal when establishing the desired post-grind rail profile.

This paper explores recent developments in the identification and subsequent managed removal of rail corrugations with an end goal of the reestablishment of rail profile with minimal metal removal and maximum preservation of rail life. The principal behind the corrugation identification system is described with supporting experimental evidence. Also presented in this paper are the basis behind dynamic corrugation removal, modeling results of applying a dynamic “peak-and-plow” pattern, and a comparative study describing the simulated post-grind outcomes of applying dynamic corrugation removal versus applying traditional methods.

Topics: Rails
Commentary by Dr. Valentin Fuster
2017;():V001T01A006. doi:10.1115/JRC2017-2255.

Maintaining track geometry is key to the safe and efficient operations of a railroad. Failure to properly maintain geometry can lead to costly track structure failures or even more costly derailments. Currently, there exists a number of different methods for measuring track geometry and then if required, maintaining the track to return track geometry to specified levels of acceptance. Because of this need to have proper track geometry, tampers are one of the most common pieces of maintenance equipment in a railroad operation’s fleet. It is therefore paramount from both a cost and track time perspective to gain maximum efficiency from any one particular tamper.

Track geometry is typically measured through a variety of contact and non-contact measurement systems which can mount on a variety of different platforms. With respect to a tamper, a push buggy projector system is typically used to measure track geometry, utilizing the tamper body as the basis for the reference system, Track geometry can be measured utilizing this technology during a prerecording run. Then, the software onboard the tamper analyzes the recorded data to determine the best fit and calculate throws that achieve a better track alignment, particularly in curves. During the tamping operation, the tamper buggy system and frame adjust the track. Due to its design, track geometry measurements can only be made at low speed (roughly 4mph) which can severely affect the efficiency of the tamper. To help decrease pre maintenance inspection times, an inertial based track geometry measurement system has been developed and integrated into the tamper’s operating software. This system can mount directly to the frame of a tamper and operate at hy-rail to very low speeds. Measurements made can be fed directly into the tamper control system to guide where and how track geometry adjustments need to be made.

In addition, the capability to collect data during travel mode without the buggies extended allows for the collection of data at any time. Thus, data can be recorded when traveling back and forth to a stabling location, before and/or after grinding. This allows for synchronization of data at a later time to utilize for adjusting the track. Also, data can be collected post-work to allow for the comparison of pre and post geometry to allow for the determination of the effectiveness of a given tamping operation.

Tampers equipped with this track geometry system facilitate the foundation for an enterprise solution. Data that is measured and collected can be sent to a cloud service, in real time that will provide exception reports, health status, and rail health trend analyses. Utilizing the available technology further optimizes response time in track maintenance.

This paper will introduce this new method of mounting and completely integrating an inertial based track geometry system onto a tamper. In addition, studies will be presented which confirm the ability of this system to replicate the tamper’s projection based track geometry system. Finally, a comprehensive study on efficiency gains will be presented directly comparing a standard method of maintaining a segment via a tamper to this new method of using onboard inertial track geometry measurement.

Topics: Geometry
Commentary by Dr. Valentin Fuster
2017;():V001T01A007. doi:10.1115/JRC2017-2256.

This paper employs the finite element (FE) modeling method to investigate the contributing factors to the “horizontal” splitting cracks observed in the upper strand plane in some concrete crossties made with seven-wire strands. The concrete tie is modeled as a concrete matrix embedded with prestressing steel strands. A damaged plasticity model that can predict the onset and propagation of tensile degradation is applied to the concrete material. An elasto-plastic bond model developed in-house is applied to the steel-concrete interface to account for the interface bond-slip mechanisms and particularly the dilatational effects that can produce the splitting forces. The pretension release process is simulated statically, followed by the dynamic simulations of cyclic rail seat loading. The concrete compressive strength at which the pretension in the strands is released, or release strength, affects both the concrete behavior and the bond characteristics. Three concrete release strengths, 3500, 4500 and 6000 psi, are considered in the simulations. Concrete tie models without and with a fastening system are developed and simulated to examine the effect of embedded fastener shoulders and fastener installation. The fastener shoulders are seated relatively deeply reaching between the two rows of strands.

There is instant concrete material degradation adjacent to the strand interfaces near the tie ends upon pretension release. Without the fastening system in the model, the 3500 psi release strength leads to a high degree of degradation that is coalesced and continuous in the upper and lower strand planes, respectively. The damage profiles with the higher release strengths are more discrete and disconnected. Dynamic loading appears to increase the degree of degradation over time. In all cases, the upper strand plane is not dominant in the degree or the extent of material degradation, in contrast to the field observations that the horizontal splitting occurred in the upper strand plane only.

Further simulations with the fastener model at 3500 psi concrete release strength indicate that the fastener installation process does not worsen the damage profile. However, the presence of fastener shoulders in the concrete matrix changes the stress distribution and redirects more concrete damages to the upper strand plane, while leaving disconnected damages in the lower strand plane. Under repeated dynamic rail loading, this potentially reproduces the exact upper strand plane, horizontal cracking pattern observed in the field. Subjected to further experimental verification, the FE analyses identify three contributing factors to the horizontal macro-cracks occurring at the specific upper strand level: (1) relatively low concrete release strength during production, (2) embedded fastener shoulders that redistribute concrete damages to the upper strand plane, and (3) a sufficiently large number of dynamic rail loading cycles for the microscopic damages to develop into macro-cracks. The number of dynamic loading cycles needed to produce macro-cracks should increase with the increased concrete release strength.

Commentary by Dr. Valentin Fuster
2017;():V001T01A008. doi:10.1115/JRC2017-2261.

The support structure beneath railroad tracks may appear to be a simple layering of various materials, but rather, it is a complex system working together to distribute the load of passing trains. It is paramount that this structure maintain its designed support properties not only to preserve component life expectancy but to maintain the safety of the trains traveling over the rails.

During normal operations, track geometry, as evaluated through the standard deviation of various track geometry channels, tends to degrade over time. This is a byproduct of the cyclical loading applied to the track structure by passing trains causing the slow compacting and settling of the ballast and sub-structure. Assuming all variables are held constant, a regular maintenance schedule should bring track geometry back into acceptable limits, but this is generally not the case in real life. In the event that the subgrade cannot support and distribute the pressure caused from the passing train successfully, accelerated track geometry degradation can take place. This accelerated degradation can be further increased when there exists a transition between support strengths which can lead to increased dynamic loading.

A case study in sub-structure pressure management has been devised and applied to a high speed rail line. During a recent track renewal operation where track was maintained down to the subgrade, pressure transducers were placed within the sub-grade layer under both the left and right rails, inside and outside of track regions where sub-structure management has been applied. This test segment was monitored over a period of one year with both pressure and track geometry data being recorded at regular intervals.

This paper will explore the relationship between sub-structure pressure and local track geometry measurements as it relates to the monitored test segment with a region of known subgrade management transition. Numerous numerical techniques will be applied to understand the change over time of the subgrade pressure distribution capability (measured as pressure beneath the rail) and the degradation of various track geometry channels individually over time. Correlation of the pressure data to track geometry data will also be done using both raw data and data processed using numerical techniques. This will lead to an understanding of how the quality of the track support structure, specifically the track support structure’s ability to distribute pressure, can affect the magnitude and degradation rates of various track geometry channels.

Topics: Pressure , Geometry
Commentary by Dr. Valentin Fuster
2017;():V001T01A009. doi:10.1115/JRC2017-2277.

While timber crossties are widely used in North America, the popularity of concrete crossties has increased significantly in recent years. Concrete crossties require the use of premium elastic fastening systems to have a proper and stable system.

The primary role of fastening system is to attach the rail to its support preserving track geometry. For this reason, past research has focused on its development and behavior. Even though a large amount of research has been conducted on heavy-haul freight railroad systems, little work has been conducted to focus on rail transit systems. Therefore, a field analysis of the behavior of fastening systems under rail transit system loading conditions has been executed, focusing on light rail transit loading conditions.

To perform this study, revenue service field data were collected on a light rail transit system. The instrumentation used and how it was installed on site are described in this paper. The critical quantitative metric discussed in this study is the relative displacement of the rail with respect to the concrete crosstie. Analyzing vertical and horizontal displacements, as well as rotation, the performance of the fastening system can be evaluated. For this purpose, different sites on the same rail system were selected for study, comparing both curve and tangent track geometry. In addition to this, the movement of the rail under every axle of the light rail vehicle has been studied in detail.

In summary, an analysis of how the rail performs in terms of displacement under light rail transit loading conditions has been completed. Based on field data, the analysis allows the reader to understand how the rail displaces under the given loads when it is installed in a ballasted concrete crosstie track and restrained by elastic fastening systems.

Commentary by Dr. Valentin Fuster
2017;():V001T01A010. doi:10.1115/JRC2017-2286.

The performance of ballasted railway systems is commonly compromised by the infiltration of fine material into the voids of the ballast. This sand and finer grained materials in the ballast is known as fouling. Increased fouling can cause decreases in hydraulic conductivity and shear strength of the ballast, as well as reduce stiffness and resilient modulus of the overall track system. These problems can cause gradual deterioration of the track, which could eventually require maintenance. One of the largest source of fouling comes from ballast breakdown resulting from abrasion caused under repeated loading. This study aims to investigate the effects of fouling from ballast breakdown on the bearing capacity of the substructure that supports the rail superstructure. Previous investigations at the University of Massachusetts Amherst utilized large scale 10-inch (25.4 cm) diameter triaxial tests on granitic ballast with fouling from ballast breakdown. The tests were run with fouling contents of 0% (clean ballast), 15%, and 30% and at water contents varying from dry ballast to field capacity. Confining pressures of 5 psi (34.5 kPa), 10 psi (68.9 kPa) and 15 psi (103.4 kPa) were used in this series of tests. Using the results from these tests, the Mohr-Coulomb strength properties can be determined for each case. This study will make use of the strength properties obtained from the results of these tests and apply them using two commonly used bearing capacity analyses. The first model is the Meyerhof and Hanna Method which considers the track as a continuous footing over a layered system. This model considers two modes of failure; punching of an individual sleeper, and track system bearing. The second model applied is the slope stability method, which uses a two-dimensional limit equilibrium approach and the method of slices to determine a factor of safety against slope stability. This analysis is commonly performed using various software programs. In this study, SLOPE/W from the GeoStudio software package is utilized for analysis. The factors of safety resulting from the bearing capacity analysis using these two methods will be compared for each of the test configurations performed, which will help to confirm the results of the analyses. Since the Mohr-Coulomb strength properties change with the degree of fouling and the water content of the ballast, it is expected that this will have some effect on the bearing capacity of the track substructure. The results of these analyses showing the effects of water content and fouling of ballast on overall track substructure bearing capacity are presented in this paper.

Commentary by Dr. Valentin Fuster
2017;():V001T01A011. doi:10.1115/JRC2017-2287.

The research presented herein focuses on determining the amount of internal prestressing force and bending resistance that is necessary to provide a durable long-term concrete railroad tie. In order to accomplish this, the researchers conducted a systematic evaluation of existing concrete ties that successfully withstood over 25 years of service in track. An experimental method for determining the remaining prestress force in these existing prestressed concrete railroad ties is currently under development.

The ties are first loaded in the upside-down orientation, with supports located at the rail seats, and two point loads applied at the center of the tie. A loading rate of 1,000 lb/min was used to initiate flexural cracking in the center of the tie. Once cracking was observed, the ties underwent 200 cycles of loading to reduce the friction between the prestressing tendons and the concrete. When the cycling was completed, the existing crack was instrumented with an extensometer to measure the Crack Opening Displacement (COD). The ties were loaded once more at 1,000 lb/min to develop a Load vs. COD relation.

A systematic method of determining the load required to reopen the crack from the Load vs. COD relation is being developed using ties cast at a manufacturing plant that were instrumented with internal vibrating-wire strain gages. Using the load required to reopen the crack, along with the known cross-sectional properties at the center of the tie, the remaining prestress force is calculated through equilibrium of forces. This method allows for the determination of the remaining prestress force in a member with known section properties to be obtained through load testing.

Commentary by Dr. Valentin Fuster
2017;():V001T01A012. doi:10.1115/JRC2017-2296.

Current research is attempting to develop a comprehensive understanding of the material and manufacturing characteristics that have caused splitting failures in prestressed concrete railroad ties, in contrast with those characteristics that have resulted in ties that have performed well after many years in track. As part of this effort, a three-dimensional (3D) Optical Scanning System is being used to accurately scan and quantify the surface geometry and volume (abrasion and wear) of a large sample of previously manufactured ties. A commercially-available 3D Laser-Based Optical Scanning System, having a maximum spatial resolution of approximately 0.1mm, is being used to perform the surface scanning operation. The scanning procedure ideally produces an accurate 3D CAD model of the tie geometry, which can then be analyzed to determine the desired geometrical features at any given cross-section. It can likewise yield a measure of the tie volume, the variation of which gives some direct indication of the extent of abrasion and wear.

The feasibility of the scanning system has previously been demonstrated by extracting the detailed longitudinal variation of geometrical cross-section crosstie parameters of a typical CXT tie, including cross-sectional area, centroid, moment of inertia, and the eccentricity of the prestressing wires. These parameters are also known to be of importance to the accurate determination of transfer length from measured surface strain. The CXT tie geometry provides an excellent test case, and a challenge to the optical scanning system, since it has a complex scalloping along its length.

While the basic feasibility of the system operation has been demonstrated, the repeatability of the geometrical information obtained from the overall scanning and subsequent post-processing of surface geometrical data has yet to be assessed.

The main objective of this paper is to first demonstrate the volumetric measurement resolution experimentally by conducting repeated scans of the same tie by the same operator. The experimental scatter in scan results is presented for both cross-section parameter detail and tie volume assessment. The statistical variation in the measured tie volume ideally provides a reasonable measure of the expected volume resolution. In addition to assessing the statistics of these repeated scans, a CXT tie was subjected to induced abrasions of known (measurable) volume for direct comparison with the volume measurements obtained using the optical scanning procedure. This work represents an important next step toward identifying the accuracy of the assessment of abrasion and wear for the large number of ties currently being scanned after having been in long-term service.

Commentary by Dr. Valentin Fuster
2017;():V001T01A013. doi:10.1115/JRC2017-2297.

Transfer length has been identified as a key diagnostic parameter for evaluating the load bearing capability of prestressed concrete railroad crossties. Furthermore, it has been proposed for use as a valuable quality control parameter. However, until quite recently the capability to easily and accurately measure transfer length has been limited primarily to a laboratory setting. This is especially true for measurements made in the harsh environment of a tie manufacturing plant. The development of portable non-contact optical strain sensors has opened the door to rapid in-plant transfer length measurement. The measurement capability of these devices has been repeatedly demonstrated not only in the laboratory, but more importantly also through actual testing at multiple tie manufacturing plants. The latest version of the automated Laser-Speckle Imaging (LSI) system developed by the authors offers improved optical resolution of longitudinal surface strain, with the ability to resolve longitudinal prestressed concrete crosstie surface strain without time-consuming special surface preparation. The new system is also capable of making measurements of strain in a real-time “on-the-fly” manner over the entire distance range of interest on the tie associated with transfer length development. This faster capability to capture the strain profile with high resolution makes this new technology very beneficial for field testing and in-plant diagnostics applications. It has been demonstrated to be capable of resolving minor differences in longitudinal surface strain profiles associated with ties even in adjacent cavities.

As a logical next step toward eventual implementation of transfer length as a quality control parameter, it is important to evaluate the expected variation of transfer length during the tie manufacturing process. This paper presents the results of extensive in-plant assessment of transfer length in an attempt to characterize experimentally the in-plant manufacturing variations that can occur in practice. To the best of the authors’ knowledge, this is the first time extensive real-time measurements to this extent have been attempted in an actual tie manufacturing plant with the expressed purpose of statistically characterizing the variations in transfer length that take place over an entire casting bed.

A sampling of transfer lengths from well over 50 ties was determined during the manufacturing process (corresponding to over 100 transfer length measurements). The sampled tie measurement locations were distributed at different “form” locations along the casting bed, and included samplings of ties from several different “cavities” within a given form. The entire bed was 45 forms in length, each form having 6 tie cavities, for a total bed size of 270 ties. The statistical distribution of overall transfer length measurement results is presented, along with what may be typical variations in strain profile and resulting transfer length as a result of variations that took place in the manufacturing process. The overall range of transfer length observed, along with an investigation of possible bias due to position within the casting bed, and apparent variations of transfer length within a given form, are identified and discussed.

Commentary by Dr. Valentin Fuster
2017;():V001T01A014. doi:10.1115/JRC2017-2322.

The ballast layer serves as a major structural component in typical ballasted railroad track systems. When subjected to an external load, ballast particles present a complex mechanical response which is strongly dependent on particle to particle interactions within this discrete medium. One common test used to study the shear strength characteristics of railroad ballast is the Direct Shear Test (DST). However, it is often not feasible in standard geotechnical engineering laboratories to conduct direct shear tests on ballast particles due to significantly large specimen and test setup requirements. Even for the limited number of laboratories equipped to accommodate the testing of such large specimens, conducting repeated tests for parametric analysis of different test and specimen parameters on shear strength properties is often not feasible. Numerical modeling efforts are therefore commonly used for such parametric analyses. An ongoing research study at Boise State University is using the Discrete Element Method (DEM) to evaluate the effects of varying particle size and shape characteristics (i.e., flakiness, elongation, roundness, angularity) on direct shear strength behavior of railroad ballast. A commercially available three-dimensional DEM package (PFC3D®) is being used for this purpose. In numerical modeling, railroad ballasts can be simulated using spheres (simple approach) and non-breakable clumps (complex approach). This paper utilizes both approaches to compare the ballast stress-strain response as obtained from DST. Laboratory test results available in published literature are being used to calibrate the developed numerical models. This paper presents findings from this numerical modeling effort, and draws inferences concerning the implications of these findings on the design and construction of railroad ballast layers.

Commentary by Dr. Valentin Fuster
2017;():V001T01A015. doi:10.1115/JRC2017-2323.

This study focused on development and characterization of a multifunctional coating system for rail track applications, such as low solar absorption, long-term durability, and corrosion resistance. Both laboratory and field experiments were conducted using coated and uncoated rails exposed to sunlight at various ambient temperatures to evaluate the effectiveness of coating in reducing rail temperature. The experimental results show that the average temperature reduction provided by the coating was 10–25°F, depending on the peak air temperature and measurement method. The effect of measurement method on rail temperature was investigated using different instrumentation types (magnet sensor, thermocouple, and automated Salient system) and thermal modelling simulations. On the other hand, the coated rail segments were placed in to the accelerate corrosion testing in a customized chamber to evaluate the performance of coating under exposure of wet/dry and freeze/thaw cycles, UV radiation, and salt spray. The performance of the coated rail segments placed in the outdoor environment and the coated rail track at service were used to evaluate the durability of coating. Field application of coating demonstrates that the coating adheres well to the rails. The curing time is about an hour. The coating can be applied on active tracks with proper scheduling. The durability of the coating was observed over two winter seasons.

Commentary by Dr. Valentin Fuster

Rail Equipment Engineering

2017;():V001T02A001. doi:10.1115/JRC2017-2205.

The fatigue crack growth rates of three vertical split rim (VSR) wheel fractures are calculated using the Paris-Erdogan fatigue crack growth equation. Initial crack length, final crack length were measured for three wheels that have experienced VSR failures. The results of the calculations indicate the lives after crack initiation are relatively short. The results of these calculations indicate the timely reduction of the number of VSR failures should emphasize the prevention of the initiation of the VSR cracks.

Commentary by Dr. Valentin Fuster
2017;():V001T02A002. doi:10.1115/JRC2017-2206.

The mission of the U.S. Transportation Security Administration (TSA) is protection of the nation’s transportation systems to ensure freedom of movement for people and commerce. In furtherance of its mission, TSA’s Office of Security Capabilities has contracted with Transportation Technology Center, Inc. (TTCI) and Arup North America Ltd (Arup) to conduct research to quantify the vulnerability of railcars and infrastructure to damage caused by the use of explosives. The main objectives of the ongoing research program are to develop tools to evaluate the performance of existing railcar structures, develop potential mitigation measures for current railcars, and investigate future advanced designs under blast conditions. TTCI performed a series of full-scale tests on three major passenger railcar types: light rail, commuter and transit. Test scenarios were developed based on extensive risk assessment and historical data. Tested scenarios include single internal charges in various locations, simultaneous internal charges and external charges on a station platform. Well instrumented tests provide experimental assessments of existing railcars’ blast performance and data for validation and refinements of finite element blast models developed by Arup. The blast models incorporate sophisticated computational fluid dynamics (CFD) modeling of blast events to predict blast wave propagation and pressure applied on the structure. Hitherto research has focused on the railcar structure. However the test series has provided information on damage to infrastructure, including rail, ties, ballast, and both catenary and third-rail electrification systems. The finite-element blast models will provide railcar designers the means to investigate the effects of blast mitigation measures and reduce the need for physical tests. Several mitigation measures were installed and tested to evaluate their effectiveness. One car was equipped with typical interior components including seats and partition walls. One side of the car was equipped with standard components and the other side with remedial components that are intended to mitigate the effects of a blast. A similar approach was used for windows. This configuration allowed direct comparisons and performance assessments of the blast mitigation measures. Companion modeling and finite element analysis (FEA) of the blast response of the railcar and interior components provided a computational tool by which mitigation measures may be assessed and refined. This paper summarizes recent research sponsored by TSA and conducted by TTCI and Arup on blast vulnerability of railcars and infrastructure to damage caused by the use of explosives.

Commentary by Dr. Valentin Fuster
2017;():V001T02A003. doi:10.1115/JRC2017-2245.

Crude oil and ethanol unit train derailments sometimes result in the release of large volumes of flammable liquids which ignite and endanger the safety of persons, property, and the environment. Current methods to reduce the probability and mitigate the consequences of High-Hazard Flammable Train (HHFT) derailments include operational speed constraints, enhanced tank car design/build requirements, improved car and track inspection and maintenance, and use of advanced braking systems. The train brake system can dissipate more energy in a derailment scenario if the brake signal propagation rate is increased, the brake force against the wheel tread is increased, or a combined approach is used.

This paper describes a simplified energy conservation model used to determine the emergency braking stopping distance and energy dissipation benefits available for three advanced train braking systems. A 3×3 matrix of brake configurations was defined by three brake signal propagation rates and three car net braking ratio (NBR) values. The brake signal propagation rate was modeled for trains with conventional head-end locomotive power, pneumatic car braking, and no two-way end-of-train device (CONV); locomotive distributed power with pneumatic car braking (trailing DP); and locomotive power with electronically-controlled pneumatic (ECP) braking. Car NBR values of 10, 12.8, and 14 percent were selected to reflect the expected brake force range available from older equipment in the existing tank car fleet (10% NBR) to the maximum acceptable value for new or rebuilt cars (14% NBR).

Various in-train emergency brake application scenarios for loaded unit trains were modeled while accounting for the gross effects of derailment/collision blockage forces. Empirical data from four trailing distributed power train derailment events were used to estimate an average derailment/collision blockage force (ADF) and simulate the trailing consist braking performance. The ADF results were subsequently used in a more general tank car unit train parametric study to evaluate the effects of train speed, track grade, and in-train derailment position for each brake configuration in the matrix. The simplified energy conservation model was used to 1) quantify the number of trailing consist cars expected to stop short of the derailment location and 2) compare the car-by-car energy state of each car in the trailing consist that was calculated to reach the derailment location. Results for the empirical and parametric study cases are compared graphically and observations are discussed relative to two assumed baseline brake configurations.

Commentary by Dr. Valentin Fuster
2017;():V001T02A004. doi:10.1115/JRC2017-2248.

The Federal Railroad Administration’s Office of Research and Development is conducting research into passenger locomotive fuel tank crashworthiness. A series of impact tests is being conducted to measure fuel tank deformation under two types of dynamic loading conditions — blunt and raking impacts. The results of this research program assist in development of appropriate standards for puncture resistance requirements to be applied to alternatively-designed fuel tanks, such as on diesel multiple unit (DMU) passenger rail equipment. This paper describes the results of the first blunt impact test performed on a DMU fuel tank.

On June 28, 2016, FRA performed a dynamic impact test of a fuel tank from a DMU rail vehicle. The test was performed at the Transportation Technology Center (TTC) in Pueblo, Colorado. An impact vehicle weighing approximately 14,000 pounds and equipped with a 12-inch by 12-inch impactor head struck the bottom surface of a DMU fuel tank mounted vertically on an impact wall. The impact occurred on the bottom of the fuel tank at a location centered on two baffles within the fuel tank. The target impact speed was 11.5 mph, and the measured impact speed 11.1 mph. The test resulted in a maximum indentation of approximately 8 inches, the bottom of the tank bending away from the wall, and buckling of several internal baffles. Following the test, the tank was cut open to inspect the damage to the internal structure. This revealed that the buckling behavior of the baffles was isolated to the baffles immediately adjacent the impact location, each one buckling as the tank deformed inward.

Prior to the test, finite element analysis (FEA) was used to predict the behavior of the tank during the test. The FE model of the tank required material properties to be defined in order to capture plastic deformation. The combination of metal plasticity, ductile failure, and element removal would permit the model to simulate puncture for this tank at sufficiently-high impact speeds. The pre-test FE model results compared very favorably with the test measurements, and both the pre-test model and the test resulted in similar modes of deformation to the DMU fuel tank. Following the test, material coupons were cut from undamaged areas of the fuel tank and subjected to tensile testing. The post-test FE model was updated with the material behaviors from the post-test material testing.

This test is part of a research program investigating puncture resistance of passenger locomotive fuel tanks. The objective of this research program is to establish the baseline puncture resistance of current locomotive fuel tanks under dynamic impact conditions and to develop performance requirements for an appropriate level of puncture resistance in alternative fuel tank designs, such as DMU fuel tanks.

Future tests are planned within this research program. The lessons learned during the series of tests support finite element (FE) modeling of impact conditions beyond what was tested. Additional tests investigating the puncture resistance of fuel tanks during sideswipe or raking collisions are also planned.

Commentary by Dr. Valentin Fuster
2017;():V001T02A005. doi:10.1115/JRC2017-2249.

Research to develop new technologies for increasing the safety of passengers and crew in rail equipment is being directed by the Federal Railroad Administration’s (FRA’s) Office of Research, Development, and Technology. Crash energy management (CEM) components which can be integrated into the end structure of a locomotive have been developed: a push-back coupler and a deformable anti-climber. These components are designed to inhibit override in the event of a collision. The results of vehicle-to-vehicle override, where the strong underframe of one vehicle, typically a locomotive, impacts the weaker superstructure of the other vehicle, can be devastating. These components are designed to improve crashworthiness for equipped locomotives in a wide range of potential collisions, including collisions with conventional locomotives, conventional cab cars, and freight equipment.

Concerns have been raised in discussions with industry that push-back couplers may trigger prematurely, and may require replacement due to unintentional activation as a result of service loads. Push-back couplers are designed with trigger loads meant to exceed the expected maximum service loads experienced by conventional couplers. Analytical models are typically used to determine these required trigger loads. Two sets of coupling tests are planned to demonstrate this, one with a conventional locomotive equipped with conventional draft gear and coupler, and another with a conventional locomotive retrofit with a push-back coupler. These tests will allow a performance comparison of a conventional locomotive with a CEM-equipped locomotive during coupling. In addition to the two sets of coupling tests, car-to-car compatibility tests of CEM-equipped locomotives, as well as a train-to-train test are also planned. This arrangement of tests allows for evaluation of the CEM-equipped locomotive performance, as well as comparison of measured with simulated locomotive performance in the car-to-car and train-to-train tests.

The coupling tests of a conventional locomotive have been conducted, the results of which compared favorably with pre-test predictions. In the coupling tests of a CEM-equipped locomotive, the coupling speed for which the push-back coupler (PBC) triggers will be measured. A moving, CEM-equipped locomotive will be coupled to a standing cab car. The coupling speed for the first test will be low, approximately 2 mph. The test will then be repeated with the speed increasing incrementally until the PBC triggers.

This paper describes the fabrication, retrofit, test requirements, and analysis predictions for the CEM coupling tests. The equipment to be tested, track conditions, test procedures, and measurements to be made are described. A model for predicting the longitudinal forces acting on the equipment and couplers has been developed, along with preliminary predictions for the CEM coupling tests.

Commentary by Dr. Valentin Fuster
2017;():V001T02A006. doi:10.1115/JRC2017-2250.

Adequate lubrication in railroad bearings is crucial to the safe operation of these components. An investigation of the residual life of railroad bearing grease was conducted in a laboratory setting. The data was collected using a split-split-plot design of experiments. The Oxidation Induction Time (OIT), which is the time required for the remaining antioxidants in a sample of grease to be consumed in a test, is the response variable for this study. Low values of OIT indicate small remaining amounts of antioxidants in the grease and thus small remaining residual life in the grease. OIT measurements were made using differential scanning calorimetry. Laboratory testing was performed utilizing a specialized dynamic test rig that allowed four rail-road bearings of the same class, mounted on a test axle, to be subjected to varying operating conditions. The independent factors manipulated in this study were total service mileage, miles at load, average speed, mounted lateral spacing, and average temperature at three locations within each bearing. Additional information was recorded for each axle tested that includes axle number, bearing location within the test axle, grease location within each bearing and the presence or absence of a small sprall on the bearing surface. Regression analysis was employed to fit mixed effects models using JMP software. The first modeling effort was to develop the best possible model for laboratory usage. A second modeling effort was conducted to develop a model for industry usage without several variables available only in the laboratory setting. Web-based applications are provided for users to investigate the residual life of railroad bearing grease in both laboratory and industry settings.

Topics: Bearings , Railroads
Commentary by Dr. Valentin Fuster
2017;():V001T02A007. doi:10.1115/JRC2017-2257.

Thermoplastic elastomers (TPE’s) are increasingly being used in rail service in load damping applications. They are superior to traditional elastomers primarily in their ease of fabrication. Like traditional elastomers they offer benefits including reduction in noise emissions and improved wear resistance in metal components that are in contact with such parts in the railcar suspension system. However, viscoelastic materials, such as the railroad bearing thermoplastic elastomer suspension element (or elastomeric pad), are known to develop self-heating (hysteresis) under cyclic loading, which can lead to undesirable consequences. Quantifying the hysteresis heating of the pad during operation is therefore essential to predict its dynamic response and structural integrity, as well as, to predict and understand the heat transfer paths from bearings into the truck assembly and other contacting components. This study investigates the internal heat generation in the suspension pad and its impact on the complete bearing assembly dynamics and thermal profile. Specifically, this paper presents an experimentally validated finite element thermal model of the elastomeric pad and its internal heat generation. The steady-state and transient-state temperature profiles produced by hysteresis heating of the elastomer pad are developed through a series of experiments and finite element analysis. The hysteresis heating is induced by the internal heat generation, which is a function of the loss modulus, strain, and frequency. Based on previous experimental studies, estimations of internally generated heat were obtained. The calculations show that the internal heat generation is impacted by temperature and frequency. At higher frequencies, the internally generated heat is significantly greater compared to lower frequencies, and at higher temperatures, the internally generated heat is significantly less compared to lower temperatures. However, during service operation, exposure of the suspension pad to higher loading frequencies above 10 Hz is less likely to occur. Therefore, internal heat generation values that have a significant impact on the suspension pad steady-state temperature are less likely to be reached. The commercial software package ALGOR 20.3TM is used to conduct the thermal finite element analysis. Different internal heating scenarios are simulated with the purpose of obtaining the bearing suspension element temperature distribution during normal and abnormal conditions. The results presented in this paper can be used in the future to acquire temperature distribution maps of complete bearing assemblies in service conditions and enable a refined model for the evolution of bearing temperature during operation.

Commentary by Dr. Valentin Fuster
2017;():V001T02A008. doi:10.1115/JRC2017-2260.

The railroad industry utilizes wayside detection systems to monitor the temperature of freight railcar bearings in service. The wayside hot-box detector (HBD) is a device that sits on the side of the tracks and uses a non-contact infrared sensor to determine the temperature of the train bearings as they roll over the detector. Various factors can affect the temperature measurements of these wayside detection systems. The class of the railroad bearing and its position on the axle relative to the position of the wayside detector can affect the temperature measurement. That is, the location on the bearing cup where the wayside infrared sensor reads the temperature varies depending on the bearing class (e.g., class K, F, G, E). Furthermore, environmental factors can also affect these temperature readings. The abovementioned factors can lead to measured temperatures that are significantly different than the actual operating temperatures of the bearings. In some cases, temperature readings collected by wayside detection systems did not indicate potential problems with some bearings, which led to costly derailments. Attempts by certain railroads to optimize the use of the temperature data acquired by these wayside detection systems has led to removal of bearings that were not problematic (about 40% of bearings removed were non-verified), resulting in costly delays and inefficiencies. To this end, the study presented here aims to investigate the efficacy of the wayside detection systems in measuring the railroad bearing operating temperature in order to optimize the use of these detection systems. A specialized single bearing dynamic test rig with a configuration that closely simulates the operating conditions of railroad bearings in service was designed and built by the University Transportation Center for Railway Safety (UTCRS) research team at the University of Texas Rio Grande Valley (UTRGV) for the purpose of this study. The test rig is equipped with a system that closely mimics the wayside detection system functionality and compares the infrared sensor temperature reading to contact thermocouple and bayonet temperature sensors fixed to the outside surface of the bearing cup. This direct comparison of the temperature data will provide a better understanding of the correlation between these temperatures under various loading levels, operating speeds, and bearing conditions (i.e. healthy versus defective), which will allow for an optimization of the wayside detectors. The impact on railway safety will be realized through optimized usage of current wayside detection systems and fewer nonverified bearings removed from service, which translates into fewer costly train stoppages and delays.

Commentary by Dr. Valentin Fuster
2017;():V001T02A009. doi:10.1115/JRC2017-2262.

Prevention of bearing failures which may lead to catastrophic derailment is a major safety concern for the railroad industry. Advances in bearing condition monitoring hold the promise of early detection of bearing defects, which will improve system reliability by permitting early replacement of failing components. However, to minimize disruption to operations while providing the maximum level of accident prevention that early detection affords, it will be necessary to understand the defect growth process and try to quantify the growth speed to permit economical, non-disruptive replacement of failing components rather than relying on immediate removal upon detection. The study presented here investigates the correlation between the rate of surface defect (i.e. spall) growth per mile of full-load operation and the size of the defects. The data used for this study was acquired from defective bearings that were run under various load and speed conditions utilizing specialized railroad bearing dynamic test rigs operated by the University Transportation Center for Railway Safety (UTCRS) at the University of Texas Rio Grande Valley (UTRGV). Periodic removal and disassembly of the railroad bearings was carried out for inspection and defect size measurement and documentation. Castings were made of spalls using low-melting, zero shrinkage Bismuth-based alloys so that a permanent record of the full spall geometry could be retained. Spalls were measured using optical techniques coupled with digital image analysis and also with a manual coordinate measuring instrument with the resulting field of points manipulated in MatLab™ and Solidworks™. The spall growth rate in area per mile of full-load operation was determined and, when plotted versus spall area, clear trends emerge. Initial spall size is randomly distributed as it depends on originating defect depth, size, and location on the rolling raceway. The growth of surface spalls is characterized by two growth regimes with an initial slower growth rate which then accelerates when spalls reach a critical size. Scatter is significant but upper and lower bounds for spall growth rates are proposed and the critical dimension for transition to rapid spall growth is estimated. The main result of this study is a preliminary model for spall growth which can be coupled to bearing condition monitoring tools to permit economical scheduling of bearing replacement after the initial detection of spalls.

Topics: Bearings , Railroads
Commentary by Dr. Valentin Fuster
2017;():V001T02A010. doi:10.1115/JRC2017-2265.

This paper presents the result of an evaluation program for the condition of the SEPTA Broad Street subway car shells and their capability to perform during an extended period of revenue service. SEPTA currently is evaluating various system upgrades to address equipment obsolescence and reliability, and wanted to verify that the current car shells are expected to be serviceable during this extended period. The evaluation focused on two aspects of the 1982-built car shells. First, what is the current and predicted condition of the shells and, second, how does the performance of the current car shell design compare to present day designs and requirements?

Four sets of activities were done as part of this project. One-third of the fleet was randomly chosen for visual inspections. Service-induced cracks were identified at two locations: in ring welds below the doors, and on the side sill between the corner posts and the anti-climbers. The ring weld cracks have been identified on a small number of cars in the past, and SEPTA continues to monitor and reinforce these areas. The cracks between the corner posts and anticlimbers are also being monitored; to date, none of these cracks has progressed to the point that repair is required.

In parallel with the visual inspections, the car shell camber and doorway dimensions were measured on approximately 10% of the fleet. All the measured vehicles had positive camber; doorway dimensions were uniform, except for scattered individual measurements that were car-specific. This part of the evaluation concluded that the car shells are not undergoing significant degradation or cracking.

One car was instrumented with strain gauges in potential high-stress areas, and then operated at simulated full passenger-load weight over the Broad Street route. Cyclic strains imposed by simulated revenue service were measured and converted to stresses. This testing confirmed high stresses at the joint between the side sill and the body bolster. The lifetime limiting location on the car shells is in the ring welds below the doors, consistent with the results of the visual inspections. Using conservative assumptions of continuous full passenger loading and minimum material properties, the predicted lifetime to the initiation of visible cracks in this area is 7–14 years of service. This independent evaluation is consistent with the actual experience, and provided confidence in the analysis protocol. SEPTA is monitoring this location and repairing cracks as required.

Evaluation of the car shell design with regard to performance in a collision revealed that, unlike most other cars of its era, the Broad Street car shell contains provisions to manage energy absorption during a low-speed collision. Records obtained from a car repair shop showed that, when a Broad Street car had a significant non-revenue end collision, these provisions worked as intended to localize the deformation. In similar collisions, the Broad Street car shell will not perform significantly different from cars built to current industry practices.

Results from this study indicate that with continued attention to car shell condition, including regular inspections and limited repairs, the Broad Street car shells will continue to be safe and serviceable for an extended period.

Topics: Shells , Subways
Commentary by Dr. Valentin Fuster
2017;():V001T02A011. doi:10.1115/JRC2017-2284.

Two major components of rolling stock that are always of great interest when it comes to maintenance and safety related issues are car wheels and bearings. Rail car wheels are subjected to a variety of damage types due to their interaction with the track and brakes. It is important for the rail industry to detect these defects and take proper action at an early stage, before more damage can be caused to the train or possibly the track and to prevent possible safety hazards. Different inspection sensors and systems, such as wheel impact monitors, wheel profile detectors, hotbox detectors and acoustic detection technologies, are employed to detect different types of wheel and bearing defects. Usually no single sensor can accurately detect all kinds of damages and hence a combination of different sensors and systems and manual inspection by experts is used for wheel maintenance purposes and to guarantee train safety. The more complete and accurate the automatic defect detections are, the less manual examination is necessary, leading to potential savings in inspection time/resources and rail car maintenance costs. Wayside thermal and visible spectrum cameras are one option for the automatic wheel and bearing inspection. Each of these sensors has their own strengths and weaknesses. There are some types of defects that are not detectable at an early stage in the images taken by a vision camera, however these defects generate a distinctive heat pattern on the wheel or bearing that is clearly visible in the thermal imagery. On the other hand, other damages might be detectable from the visible spectrum image, but not necessarily have a distinguishable heat pattern in the thermal imagery. Since a thermal image is basically built of solely temperature data, it excludes other critical information, such as texture or color. This makes thermal and visible spectrum imagery complementary and if the images are fused the result will benefit from the strengths of both sensors. In this paper, wavelet decomposition is employed to extract the features of the thermal and vision imagery. Then the two images are merged based on their decompositions and a fused image is composed. The resulting fused image contains more information than each individual image and can be used as an input for image-based wheel and bearing defect detection algorithms. To verify the proposed method and to show an example of this application, it is demonstrated on a real data set from a Union Pacific rail line to identify sliding wheels.

Topics: Sensors , Bearings , Rails , Wheels , Damage
Commentary by Dr. Valentin Fuster
2017;():V001T02A012. doi:10.1115/JRC2017-2309.

Until the introduction of AAR Standard S-259 (circular C-8287) in November, 1994 the Class F axle was the only officially designated roller bearing axle design permitted for 100 ton freight car service in North American interchange service. The increase in Gross Rail Load permitted by the Standard was correlated to increased failures at the journal ends of the axle. A 1998 redesign of the bearing and axle resulted in lower stresses in the journal; the new axle was designated as Class K and was to be used in service loads of 100/110 tons (263,000 to 286,000 pounds GRL). The redesign was highly successful in reducing axle journal failures and improving bearing life. An increase in axle failures between the wheel seats was reported several years after the redesign. Better inspection requirements and repair procedures were implemented to reduce failures resulting from surface damage. This investigation considers the effect on stresses of the accepted practice of repairing the body of the axle by machining.

Commentary by Dr. Valentin Fuster
2017;():V001T02A013. doi:10.1115/JRC2017-2330.

Fifty years ago, the railcar industry relied entirely on classical analysis methods using fundamental solid mechanics theory to establish design and manufacturing protocols. While this method produced working designs, the assumptions required by this type of analysis often led to overdesigned railcars.

In the 1950s, the generalized mathematical approach of Finite Element Analysis (FEA) was developed to model the structural behaviors of mechanical systems. FEA involves creating a numerical model by discretizing a continuous system into a finite system of grid divisions. Each grid division, or element, has an inherent geometric shape and each element is comprised of points which are referred to as nodes. The connected pattern of nodes and elements is called a mesh. A solver organizes the mesh into a matrix of differential equations and computes the displacements using linear algebraic operations from which strains and stresses are obtained.

The rapid development of computing technology provided the catalyst to drive FEA from research into industry. FEA is currently the standard approach for improving product design cycle times that were previously achieved by trial and error. Moreover, simulation has improved design efficiency allowing for greater advances in weight, strength, and material optimization. While FEA had its roots planted in the aerospace industry, competitive market conditions have driven simulation into many other professional fields of engineering.

For the last few decades, FEA has become essential to the submittal of new railcar designs for unrestricted interchange service across North America. All new railcar designs must be compliant to a list of structural requirements mandated by the Association of American Railroads (AAR), which are listed in its MSRP (Manual of Standards and Recommended Practices) in addition to recommended practices in Finite Element (FE) modeling procedures. The MSRP recognizes that these guidelines are not always feasible to completely simulate, allowing the analyst to justify situations where deviations are necessary.

Benefits notwithstanding, FEA has inherent challenges. It is understood that FEA does not provide exact solutions, only approximations. While FEA can provide meaningful insight into actual physical behavior leading to shorter development times and lower costs, it can also create bogus solutions that lead to potential safety and engineering risks. Regardless of how appropriate the FEA assumptions may be, engineering judgment is required to interpret the accuracy and significance of the results. A constant balance is made between model fidelity and computational solve time.

The purpose of this paper is to discuss the FEA approach to railcar analysis that is used by BNSF Logistics, LLC (BNSFL) in creating AAR compliant railcar designs. Additionally, this paper will discuss the challenges inherent to FEA using experiences from actual case studies in the railcar industry. These challenges originate from assumptions that are made for the analysis including element types, part connections, and constraint locations for the model. All FEA terminology discussed in this paper is written from the perspective of an ANSYS Mechanical user. Closing remarks will be given about where current advances in FEA technology may be able to further improve railcar industry standards.

Topics: Simulation , Design
Commentary by Dr. Valentin Fuster

Signal and Train Control Engineering

2017;():V001T03A001. doi:10.1115/JRC2017-2202.

Recently the demand of wireless communications technology in railway field has increased for the purpose of safe operation and economical construction and reducing operating costs. The real implementation test was carried out in order to apply the next generation ITS wireless communication technology (WAVE: Wireless Access Vehicular Environment) to the railway. WAVE communication is suitable for high-speed environment, have a reliable wireless communication performance. This paper presents the results of test about installing the WAVE base station / WAVE Terminal for applying to the railway and measure the performance evaluation conducted.

Topics: Railroads
Commentary by Dr. Valentin Fuster
2017;():V001T03A002. doi:10.1115/JRC2017-2204.

IEEE 1698, Guidelines for Safe Braking Distance Calculations - 2009 brakes down the determination of stopping distance for train control system into separate independent events. One of the most misunderstood portions of the model is Parts I and H (train deceleration). This paper looks at the reasoning behind the unique properties of these parts, how they are related as well as how to calculate them. Examples of applications will be shown and optimization techniques will be investigated to shorten the required safe stopping distance and increase capacity.

Topics: Braking
Commentary by Dr. Valentin Fuster
2017;():V001T03A003. doi:10.1115/JRC2017-2214.

A key assumption in the process of optimized design of RF systems is the efficient transfer of power from the transmitter source to the load (i.e., the end antenna). Unless the transmitter is located directly next to the load, a transmission circuit comprised of multiple cascaded or forked segments connects one to the other. An example of such transmission network is the RF transmission chain of the Communication-Based Train Control (CBTC) trackside antenna system. The system design requirement and validation process necessitates development of means for realistic evaluation and analysis of the reflection and insertion loss values offered by the trackside RF chains of a radio-based CBTC system. The aim of this research is to present a comparative study of three different models developed to quantitatively assess reflection and insertion losses in a general multi-stage RF transmission network. To provide a more realistic and credible assessment, the comparison has been further substantiated with measurement data.

Commentary by Dr. Valentin Fuster
2017;():V001T03A004. doi:10.1115/JRC2017-2243.

American Railroads are planning to complete implementing their Positive Train Control (PTC) systems by 2020. Safety objectives of PTC are to avoid inter-train collisions, train derailments and ensuring railroad worker safety. Under published specifications of I-ETMS (the PTC system developed by Class I freight railroads), the on-board PTC controller communicates with two networks; namely, the Signaling network and the Wayside Interface Unit network to gather navigational information such as the positions of other trains, the status of critical infrastructure (such as switches) and any hazardous conditions that may affect the train path. By design, PTC systems are predicated on having a reliable radio network operating in reserved radio spectrum, although the PTC system itself is designed to be a real-time fail safe distributed control systems. Secure Intelligent Radio for Trains (SIRT) is an intelligent radio that is customized to train operations with the aim of improving the reliability and security of the radio communication network.

SIRT has two tiers. The upper tier has the Master Cognitive Engine (MCE) which communicates with other SIRT nodes to obtain signaling and wayside device information. To do so, the MCE communicates with cognitive engines at the lower tier of SIRT; namely the Cryptographic Cognitive Engine (CCE) (that provide cryptographic security and threat detection) and the Spectrum Management Cognitive Engine (SCE) (that uses spectrum monitoring, frequency hopping and adaptive modulation to ensure the reliability of the radio communication medium). We presented the architecture and the prototype development of the CCE in [1]. This paper presents the design of the MCE and the SCE.

We are currently developing a prototype of the SCE and the MCE and testing the performance of our cognitive radio system under varying radio noise conditions. Our experiments show that SIRT dynamically switches modulation schemes in response to radio noise and switches channels in response to channel jamming.

Topics: Trains
Commentary by Dr. Valentin Fuster
2017;():V001T03A005. doi:10.1115/JRC2017-2269.

The data communications subsystem or DCS is an important element of a CBTC system which supports the wired and wireless data communications between a CBTC equipped train and the wayside elements such as zone controllers and the automatic train supervisory (ATS) system.

A “brown field” environment (as opposed to “green field” environment) represents an existing transit system that is already in revenue service and is being re-signaled with a new CBTC system. Such an environment typically represent the most challenging deployment for CBTC a system as it must be installed, tested and integrated in such a manner as to not adversely impact the transit agencies’ ongoing revenue service. Usually, one of the first elements of a CBTC system to be designed and deployed is the DCS. This paper will examine some lessons learned related to the DCS design, deployment, testing and commissioning for CBTC projects in a “brown field” environment with a view to improving future CBTC projects.

Commentary by Dr. Valentin Fuster
2017;():V001T03A006. doi:10.1115/JRC2017-2280.

This paper provides an overview of current solutions for Cross-Border technical interoperability offered by ERTMS and introduces convergence points between the ERTMS and PTC system architectures.

Seen as an overlay system for legacy national ATP/ATC in Europe, ERTMS definition was initiated with the announced purpose of solving cross-border technical interoperability. Beyond the carrier for voice and data radio communications, the paper will introduce the current technical solutions to ensure interoperability, the building blocks and founding principles, focusing on key requirements and design choices.

The reasons for the global success of ERTMS well outside Europe will be explored, offering the author’s view on factors that influenced decision making in favor of ERTMS-based system solutions, and provided significant commercial success (end of 2014, more track-km were fitted with ERTMS outside Europe). The same system architecture that ensured technical interoperability, allowed purchasing decisions supporting ERTMS, due to perceived inter-changeability of technical components (multi-vendor supply was ensured), along with public availability of detailed system specifications and hazard analyses.

To conclude, the paper will review the convergence points between ERTMS and PTC, and offer a possible way forward into using ERTMS building blocks for a PTC solution.

Commentary by Dr. Valentin Fuster
2017;():V001T03A007. doi:10.1115/JRC2017-2293.

There is a growing trend for transit agencies to evolve from wayside and cab-based signal systems to Communication Based Train Control (CBTC). With the complexity of CBTC, a failure of CBTC component could bring a transit system to a standstill. Implementing a secondary signal system can serve to minimize the consequences of a CBTC failure. It is paramount for a transit system to continue to operate, and axle counter technology can be a suitable candidate for use as a secondary signal system. Axle Counter technology has not been widely used in the U.S., but has been used for many years in Europe and the rest of the world. This paper will review and analysis the following:

1. Train Detection Systems; Track circuits vs. axle counters and the basic Principles of Axle Counting; check-in and check-out.

2. Implementing Electromagnetic Compatibility and the EMI standards used in European with previous testing of various axle counter systems, and the frequencies that have been selected, and the proper usage of these frequencies.

3. Testing of radiated emissions using existing guidelines and methods to analyze existing wayside and vehicle Electromagnetic Interferences (EMI), environment conditions, and the limitations of installing axle counters in an existing rail or transit system.

4. Recommendations for improving vehicle and wayside specifications and standards within the U.S. for dealing with installation of axle counter equipment and with failures and EMI emissions between railway devices.

Commentary by Dr. Valentin Fuster
2017;():V001T03A008. doi:10.1115/JRC2017-2299.

The North American Freight Railroad industry has been exploring ways in which on-board real time or near real-time monitoring of important railcar components and cargo can be accomplished. This approach alleviates the danger from fast occurring catastrophic events like bearing failure, which is not always possible using the traditional wayside monitoring techniques. The use of Wireless Sensor Networks is a viable candidate technology that is being explored for this application. However, popular communication protocols based on IEEE 802.15.4 have been evaluated by the railroad industry and our lab, and were found to perform unacceptably for this application domain, among other reasons, as a consequence of the long linear chain-like network topology of a sensor network deployment on a train. Hybrid Technology Networking (HTN) protocol has been designed to address these issues. HTN structures the network as a communication hierarchy using multiple different network technologies. It allows small clusters to communicate internally using IEEE 802.15.4 and utilizes IEEE 802.11 as the inter-cluster transport method for data delivery over multiple hops to the locomotive. It aims to maximize the benefits afforded by each technology. Energy is a scarce resource in such networks and hence modeling it for energy analysis and optimization is vital. A model that accurately predicts the energy consumption of a particular network deployment is therefore of utmost necessity. However, most modelling efforts concentrate on network deployments utilizing only a single type of communication protocol and the structure of such deployments are often mesh-like. Also the existing modelling approaches tend to model the entire network as a single phenomenon, which is often not the case in network deployments such as those in the freight railroad scenario. It is also expensive to commission large network deployments to evaluate energy consumption profiles. The problem is compounded when this process has to be repeated for several different communication protocols and channel conditions. The task will be made economically viable and massively scalable with the use of a modular energy model. The philosophy behind our approach is to model the important and contributing constituents of the protocol within each node and also external to the node and then utilize inter-dependencies to connect the individual models. This work is the first step towards a modular energy model for the Hybrid Technology Network, and is also applicable to many other networking approaches. In this work we propose a model design that is capable of predicting the network behavior of nodes in a linear chain-like topology utilizing the ContikiMAC duty cycling protocol for multi-hop communication with the sink node. We have used channel emulation to test hardware nodes in a chain-like topology to validate the model predictions, and present our findings in this paper.

Topics: Topology
Commentary by Dr. Valentin Fuster
2017;():V001T03A009. doi:10.1115/JRC2017-2342.

In order to conduct rail operations safely and securely, operators need reliable train connectivity. With the advent of Intelligent Transport Systems, there are increased demands from this connectivity. This paper introduces the capabilities of 3GPP standard radio technology to meet the railway operator’s connectivity needs using a unified radio infrastructure. 3GPP is the 3rd Generation Partnership Project and provides the standards known to the public as 3G or 4G mobile telecommunications provided by the cellular phone operators. Recent developments in 3GPP standards make the technology suitable for use in both urban and mainline rail environments based on a private 4G LTE network owned and operated by the railroad agency. Since the 3GPP standard equipment ecosystem is shared by mobile operators, public safety agencies, utilities, and airports, the equipment cost is reduced compared to proprietary wireless techniques due to economies of scale. Using a dedicated radio network, all rail applications requiring wireless connectivity can traverse over a single radio infrastructure.

These rail applications include: CCTV real time passenger surveillance, mission critical push-to-talk voice, train control signalling (CBTC, ETCS or PTC), train telemetry, including real-time condition-based monitoring and passenger information systems. Using Quality of Service prioritization and pre-emption inherent to the LTE radio system, the mission critical railway applications always receive priority over non-mission critical functions. The FCC has recently announced the availability of the 3.5 GHz band to the public based on spectrum sharing. Spectrum sharing could be an acceptable option for railway application, provided it was given priority for mission critical functions. Current advances in LTE radio, notably Massive MIMO (multiple input, multiple output) antenna arrays, can provide coverage in 3.5 GHz band to a distance of over 1400 yards — which is less than the typical distance between stations. this transit agency dedicated network. Alternately sharing spectrum with Firstnet 700 MHz band should be explored.

Topics: Rails
Commentary by Dr. Valentin Fuster

Service Quality and Operations Research

2017;():V001T04A001. doi:10.1115/JRC2017-2223.

The railway traffic system is an important player in passenger and freight transportation. This paper aims to present a survey of optimization models for the most commonly studied rail transportation problems related to train scheduling. We propose a classification of models and describe their characteristics by focusing on model structure and algorithmic aspects. Most reviewed papers have been proposed during the last decades. Apart from a few exceptions, the survey concentrates on published and easily accessible material. We have also elected to limit ourselves to contributions dealing specifically with rail transportation planning in single and double tracks. Each model has different goals, such as, to minimize service delays, to reduce the unscheduled train stops or to minimize the total time a train has to remain motionless, specially to allow crossings. For each group of problems, we propose a classification of models and describe their important characteristics by focusing on model structure and algorithmic aspects. The literature review involve papers published since the 1970s, but recent publications suggest that the problem is still heavily investigated. The main approaches considered are those that focus on Mathematical Optimization and Simulation. The review also considers the approach used to generate the solution, the type of railroad (real or hypothetical), and the infrastructure characteristics used to represent the railroad model. Our analysis focuses on showing an overview of those planning models.

Topics: Trains
Commentary by Dr. Valentin Fuster
2017;():V001T04A002. doi:10.1115/JRC2017-2251.

First-mile and last-mile travel is the bottleneck of using the public transportation service. This paper considers the passenger matching and vehicle routing problem in the first-mile ridesharing service connecting train schedules. Then a mixed integer model is proposed to formulate the problem. Since the problem is NP hard, we develop a simulated annealing (SA) algorithm with four neighborhood structures to solve this problem. Experiments are designed to test the proposed model and algorithm. The experimental results verify the effectiveness of the algorithm and demonstrate that the proposed algorithm can obtain satisfactory solutions within a reasonably short time.

Commentary by Dr. Valentin Fuster
2017;():V001T04A003. doi:10.1115/JRC2017-2291.

The Brazilian Rail Regulatory Framework was reviewed in 2011 by the National In Land Transport Agency (ANTT), with the edition of a package of Regulatory Resolutions (Resolution nº. 3,694 - Regulation of General Rules for Shippers and Rail Companies, Resolution nº. 3,695 - Regulation of Trackage and Haulage Rights, and Resolution nº. 3,696 - Regulation for Stretch Production Targets and Safety Targets Procedure Agreements) with the basic objectives of: i) create incentives for rail interoperability, ii) promote intra sector competition and, hence, enhance rail role in the national transport sector, and iii) establish new funding sources for the rail sector, in order to support investments needed for increasing rail system capacity. These, together with other structural measures already adopted by ANTT, such as the regulation of investments made by rail concessionaires and the revision of rail price cap rates, complemented the package of rail regulatory measures. For the effective implementation of the principles set out in the mentioned rail regulatory framework review, however, it was necessary to develop a sort of tools to allow regulatory control and reduce asymmetric information within the actors of this important industry. Among these tools, it is highlighted the Rail Network Statement, established by Resolution ANTT nº. 3,695/2011, basically composed of a compilation of the existing rail network main operational and technical data, such as rail gauges, load capacities, operational speeds, clearances, location of locomotives and wagons repair facilities as well as fuel stations, including an inventory of traffic capacity, with a survey of available capacity in all sections of the national rail network. This dataset was intended to reduce asymmetric information between rail industry players - Regulatory Authority, Rail Carriers and Shippers, and, so, enhance the negotiation processes for interoperability operations and investments agreements. Rail Network Statement must be filed annually by Concessionaires, and after a critical analysis and data review by the regulatory agency, it is released on its website for public access to support rail interoperability planning and negotiation process. This work is supposed to present an overview of Brazilian Rail Network Statement structure, with a Case Study Analysis of 2013 Edition, the first issued, with a strong focus on rail capacity analysis, an essential requirement for rail interoperability.

Topics: Rails
Commentary by Dr. Valentin Fuster
2017;():V001T04A004. doi:10.1115/JRC2017-2306.

A new approach is presented in order to deal with disruptions in rail transport networks. A mathematical model which decides on the speed profile while considering passenger use is presented. The model decides on the optimal sequence of operating regimes and the switching points between them for a range of different circumstances and train types all while considering delays and passenger compensation policies applied by the train operator. Computational tests on realistic problem instances of the Spanish rail operator RENFE are reported. The proposed approach is able to find solutions with a very good balance between various managerial goals.

Commentary by Dr. Valentin Fuster

Planning and Development

2017;():V001T05A001. doi:10.1115/JRC2017-2273.

The Hiawatha Service is an Amtrak intercity passenger rail service that operates the 90-mile route between Milwaukee, Wisconsin, and Chicago, Illinois. As part of its management and oversight role for the route, the Wisconsin Department of Transportation (WisDOT) routinely conducts surveys of passengers traveling on the Hiawatha Service. The most recent survey was conducted in May 2016. This paper reports a summary of the key findings from the 2016 Hiawatha Service passenger survey. Analysis of more than 2,400 surveys reveals significant details of the travel behavior and demographic profile characteristics of Hiawatha Service passengers. A majority of passengers on weekday trains are traveling for work commute or business-related purposes while a majority of weekend passenger trips are leisure or personal trips. Approximately 70 percent of passengers would drive if the Hiawatha Service were not available, indicating that the train has a meaningful impact on highway congestion. Additional details on passenger motivations for using rail and the importance of on-board Wi-Fi service are also provided. Comparison of the results from 2016 with previous surveys conducted in 2002/2003, 2005, and 2011 demonstrates the role of the Hiawatha Service in the Milwaukee-Chicago travel corridor.

Commentary by Dr. Valentin Fuster
2017;():V001T05A002. doi:10.1115/JRC2017-2274.

In recent decades, many transportation agencies have adopted a performance-based strategy for developing and supporting decisions related to transportation planning. Recent Federal legislation related to intercity passenger rail planning and development has adopted numerous provisions that emphasize the role of performance measurement throughout the process. This paper reports the findings of a comprehensive synthesis of performance measurement and quality assurance techniques for intercity passenger rail service planning and development. A performance-based process can support planning and decision-making for a wide range of activities including statewide rail planning, rail corridor planning, and management of existing services. For statewide planning purposes, a performance measurement system can be used to prioritize specific intercity corridors for detailed feasibility study. For existing rail services, a performance-based process can be used to establish performance targets related to operational and customer service aspects, measure progress toward these targets, and develop strategies to achieve desired results. A regular “quality assurance” program can also be used to maintain accountability for service operators and correct deficiencies in service delivery for existing routes. States and other entities involved with the passenger rail planning process will benefit from the findings of this synthesis by providing insight into the “ideal” performance management strategy.

Commentary by Dr. Valentin Fuster

Safety and Security

2017;():V001T06A001. doi:10.1115/JRC2017-2203.

The new train signaling, traction power and tunnel ventilation system coordination guidelines enacted in National Fire Protection Association (NFPA) Standard 130 have brought the necessity and cost of tunnel ventilation fan shafts into greater focus. The guidelines were aimed at coordinating the three aforementioned rail systems to control the number of trains that could be between successive ventilation shafts during an emergency — in recognition of the fact that the best protection to both incident and non-incident train passengers and crew is to allow no more than one train in each ventilation zone. Though based in safety, these new NFPA guidelines can substantially expand the capital cost and environmental impact of new rail tunnel projects by adding more ventilation shafts and tunnel fan equipment to the scope of work. In addition, the resulting increase in the required number of ventilation shafts and tunnel fan equipment can hinder existing railroad properties as they seek to either increase their train throughput rates, or reduce their tunnel electrical infrastructure. Fortunately, a new kind of emergency ventilation shaft has been developed to facilitate compliance with the NFPA 130 Standard without the excessive capital cost and far-reaching environmental impacts of a traditional emergency ventilation shaft. This new kind of emergency ventilation shaft is called the Crossflue.

The Crossflue is a horizontal passage between parallel rail tunnels with a single ventilation fan-motor unit installation. The Crossflue fan is designed to transfer air/smoke flows from one (occupied, incident) tunnel to another (unoccupied, non-incident) tunnel — thereby protecting the incident tunnel at the expense of the non-incident tunnel. The Crossflue passage has angled construction to allow a smooth transition of airflows both into and out of the adjoining tunnels. In addition to the fan, the Crossflue contains a ventilation damper, sound attenuators, ductwork transitions and flexible connectors within the fan equipment line-up; the functionality of all this mechanical equipment is described in the paper. To preserve underground space and minimize the rock excavation, the Crossflue fan is both remotely-powered and remotely-controlled; the fan is only operated as part of a pre-programmed response to tunnel fire events. The methodology utilized to design the Crossflue was taken from the Subway Environmental Design Handbook (SEDH); the SEDH [1] was specifically developed for rail tunnel ventilation design and is the preeminent reference volume in the industry. In summary, the Crossflue provides a dual benefit of achieving NFPA 130 compliance, while at the same time minimizing the construction, equipment, environmental, and energy costs of a traditional tunnel ventilation shaft.

Topics: Ventilation , Design , Tunnels
Commentary by Dr. Valentin Fuster
2017;():V001T06A002. doi:10.1115/JRC2017-2213.

Training represents a unique opportunity to engage employees and mold their behavior to that desired by the organization and required by regulation. It is also an opportunity to reduce human factor causes of accidents through the proper application of training best practices. Underscoring the importance of comprehensive training programs, in 49 Code of Federal Regulations (CFR) Part 243, the Federal Railroad Administration (FRA) has established training requirements for safety-sensitive railroad employees. These include the requirement that railroads and railroad contractors submit to the Federal Railroad Administration a training program for review and approval. In addition to meeting regulatory requirements, comprehensive training programs can usher in broad safety improvements, reduce delays, as well as improve operational and organizational efficiency. Related to employee safety and training, this paper also discusses the importance of crew resource and fatigue management plans.

Commentary by Dr. Valentin Fuster
2017;():V001T06A003. doi:10.1115/JRC2017-2220.

In urban area, frequent train services during peak hours often keep interrupting roadway traffic approaching level crossings (LXs). In Taiwan, more than 24 trains per hour pass the LXs in peak hours, and it leads to more than 40% time blocked by the barriers. To mitigate the potential risk of accidents between trains and roadway vehicles, almost 20% LXs had been installed with obstacle detection devices. It, however, leads to the following issues: (1) when the level crossings open and then close within a short period of time, the vehicles would likely be trapped in the dangerous area; (2) if the closing time at level crossings is not adjusted effectively, it would seriously impact the traffic flow and increase the possibility of trespassing; (3) the false alarm triggered by the obstacle detection devices has serious impact on train punctuality.

To mitigate the influence on roadside traffic and improve the safety, this study developed an intelligent module which consists of the following functions: (1) transmitting real-time videos of level crossings to the approaching trains, (2) constant alarm time for trains with different approaching speeds, and (3) extending alarm time for trains from the opposite directions within short time periods. A level crossing located on curved line in urban area was selected to test the performance of these functions in an actual scenario. Alternative solutions were also adopted in the tests to compare the performance for reference. The results show that the module can be viable in practice, but needs further works to ensure the safety, such as developing a fail-safe mechanism and overcoming the software security issues.

Topics: Safety , Cities , Railroads
Commentary by Dr. Valentin Fuster
2017;():V001T06A004. doi:10.1115/JRC2017-2230.

We examine how establishing a competitive Joint Rail Conference Grand Challenges Initiatives can harness the potential of college and possibly high school students to develop solutions or new insight into technical and safety problems plaguing the rail industry, including safety.

The rail industry has tended to solve issues internally. However, solutions can often be found in other industries that are either similar or have faced similar concerns. For example, the immediate predecessor of Positive Train Control (PTC), the Advanced Railroad Electronics System (ARES), was conceived in the mid 1980’s by then Burlington Northern Railroad (BN) CEO Richard Bressler, who had read how flight safety and efficiency had been improved by air traffic control systems and avionics developed by Rockwell Collins for the Boeing 757 and 767 aircraft. The information age has further increased the potential for sparking innovation as ideas can spread literally overnight via the internet.

Some of the most talented and creative problems solvers are college and high school students, who have been greatly enabled by the “democratization” of information that has given them access to knowledge and skills as never before. Teens can learn nearly any skill watching reputable online videos or even “attend” classes offered by top universities around the world simply using a smart phone or tablet. This has prompted educators like Michigan Tech’s Dr. Pasi Lautala and other to develop extensive online rail educational resources to spark interest in the industry. However, simply passing on information has its limitation, which is why initiatives like the Grand Challenges, and Engineers without Borders have been instrumental in harnessing students to examine key global challenges in engineering, energy, and health care. Moreover, these initiatives have encouraged many students to pursue careers in those fields, even in low- and medium-income countries. For example, in 2012, a high school sophomore developed a new method to detect pancreatic cancer that is quick to administer and detects the disease much more quickly than previous methods, allowing much better chances for successful treatment. We will examine how establishing a competitive JRC Grand Challenges Initiatives can harness the potential of college and possibly high school students to develop solutions or establish new insight into technical and safety problems plaguing the rail industry, including safety. In addition, it will look at how developing a dialog among the rail industry, including the Class 1 railroads, students, and academia can encourage a more top notch, talented students to consider careers in the rail industry.

Topics: Rails , Students
Commentary by Dr. Valentin Fuster
2017;():V001T06A005. doi:10.1115/JRC2017-2236.

Safety is a top priority for the development of worldwide high-speed rail systems. Ballast flying is a particular safety concern when a high-speed train is traveling above a certain speed on the ballasted track. Displaced ballast particles from the track may cause damages to rolling stock, as well as the track infrastructure and wayside structures close to the sides of way. The objective of this research is to develop a probabilistic modeling framework to estimate the probability of ballast flight on specific segments or routes, accounting for several principal risk factors. Based on the probabilistic assessment, we propose a methodology to quantify the probability of flying ballast under certain scenarios. The methodology can be further developed, ultimately enabling a normative risk assessment for flying ballast risk management.

Topics: High speed rail
Commentary by Dr. Valentin Fuster
2017;():V001T06A006. doi:10.1115/JRC2017-2239.

The objective of this paper is to demonstrate how GIS and data visualization systems can be used to identify spatial relationships to add to our understanding of railroad accident factors. Examples are given of the spatial analysis of broken rail accidents and grade crossing accidents on GIS maps. Additionally, using the Weave data visualization system a data dashboard was constructed that shows the complex interaction between variables like track type, FRA track classification, train speed and track density with broken rail accident causes. The findings indicate that broken rail accidents occur most frequently in the Midwest. Possibly this trend is related to climate change and increased temperatures and precipitation in the United States. GIS visualizations also showed that many truck-trailer accidents at grade crossings occur in low population areas. This work indicates that GIS and data visualizations are a useful method of identifying trends in railroad accidents.

Commentary by Dr. Valentin Fuster
2017;():V001T06A007. doi:10.1115/JRC2017-2246.

Railroad environments are generally considered to be among the most dynamic workplace environments, even with constant improvement efforts by the railroad industry. While there has been great progress in equipment safety, personnel safety is a significantly harder challenge. These challenges are primarily derived from the presence of heavy moving machinery in close proximity to personnel and the difficulty of designing reliable wearable protection devices. Additionally, variable weather conditions, challenging walking conditions (ballast, trip hazards, etc.), and difficulty to focus on environment, moving objects, and on tasks at hand place the employees in constant peril. Therefore, our survey is focused on exploring solutions for protecting employees through unified system modeling and design that makes the employee integral to the process and results in personal protective devices that work with the environment and the employee, not against them. The optimal system design integrates not only protection of the employees from falls, unsafe practices, or collisions, but also aids in resource planning, safe operation and accounting of “near-miss” situations.

In recent years the railroads have made significant investments in process automation and monitoring solutions such as Wireless Sensor Networks. These technologies are becoming increasingly cloud-connected and autonomous. They provide a plethora of information about equipment positions, movement, railcar lading, and many other factors, all of which are highly useful in the design and implementation of a railyard worker protection system. They allow us to predict position and movement, and can thus be used to provide effective proximity detection and alerting in some railyard regions where these systems are installed. Additionally, we discuss several technologies addressing near-collision, fall, and proximity situations through RF and non-RF-based techniques. The railroad industry has been advancing efforts leveraging these technologies to improve the safety of their workers.

However, there are also many challenges that remain largely unaddressed. For example, in railroads, a detailed and exhaustive causation analysis for worker incidents has yet to be conducted. Therefore, in an environment like a railyard there is no solution to detect or prevent Employee on Duty (EOD) fall, collision, or health issues such as dehydration, psychological issues and high blood pressure. Protective devices worn by workers is believed to be one of the most important, cost-effective, and scalable potential candidate solutions. Recent advances are making wearable wireless body area networks (WBAN) and wireless sensor networks (WSNs) that are distributed and large-scale a reality. Such distributed networks consist of wearable sensors, fixed-installation sensors and communication links between all of them. The challenges are found in selecting wearable sensors, researching reliable communication among nodes without interfering with proximity detection and suitable for high-multipath, non-line of sight channel conditions, wearable antenna designs, power supply requirements, etc.

A dense, distributed, large-scale environment like a railyard requires comprehensive workspace modelling and safety analysis. Interference related to RF sensor deployment, blind spots in vision-based approaches, and wireless propagation in intra and inter-WBAN communication due to dense non-Line-of-Sight workspace environments, metallic heavy machinery and the use of RF sensors, are all individual research challenges in this domain.

This paper reviews these challenges, explores potential solutions, and thus provides a comprehensive survey of a holistic system design approach for a wearable railyard worker protection system that is unobtrusive, effective, and reliable.

Topics: Design
Commentary by Dr. Valentin Fuster
2017;():V001T06A008. doi:10.1115/JRC2017-2247.

Much has been said and written about the role culture plays in the safety performance of organizations across all industries. Understanding that accidents cannot simply be blamed on those directly at fault, this paper explores organizational culture and the part it has played in contributing to the cause of rail and other transportation accidents. This paper also discusses the pivotal role of organization leaders in setting cultural norms and priorities that either bolster or hinder safety. Structure, budget, mission statement, and values, which are established by leaders, all demonstrate the importance of safety to employees and others.

At the same time, organizations focused on production run the very real risk of placing safety second. This is a particular concern with transportation providers who may be pressured to focus on performance and schedule adherence, at the cost of safety Recommendations for improvement of organizational culture are provided, with a focus on generally accepted best practices.

Commentary by Dr. Valentin Fuster
2017;():V001T06A009. doi:10.1115/JRC2017-2271.

Public agencies involved with highway-railroad grade crossing safety must allocate available funding to projects which are considered the most in need for improvements. Mathematical models provide a ranking of hazard risk at crossings and support the project selection process. This paper reports the results of a research study sponsored by the Ohio Rail Development Commission (ORDC) and the Ohio Department of Transportation (ODOT) examining hazard ranking models for grade crossing project selection. The goal of the research was to provide ORDC, ODOT, and other stakeholders with a better understanding of the grade crossing hazard ranking formulas and other methods used by States to evaluate grade crossing hazards and select locations for hazard elimination projects. A comprehensive literature review along with personal interviews of state DOT personnel from eight states yielded best practices for hazard ranking and project selection. The literature review found that more than three-quarters of states utilize some type of hazard ranking formula or other systematic method for project prioritization. The most commonly-used hazard ranking model in use is the U.S. DOT Accident Prediction Model; however, at least eleven states utilize state-specific hazard ranking models. Detailed evaluation of several different hazard ranking models determined that the existing hazard ranking model used in Ohio, the U.S. DOT Accident Prediction Model, should continue to be used. The research also recommends greater use of sight distance information at crossings and expanding the preliminary list of crossings to be considered in the annual program as enhancements to the existing project selection process used by the ORDC and ODOT.

Topics: Hazards
Commentary by Dr. Valentin Fuster
2017;():V001T06A010. doi:10.1115/JRC2017-2275.

This paper presents a risk assessment of a Liquefied Natural Gas (LNG)/diesel hybrid locomotive to identify and rank failures that could result in the release of LNG or Gaseous Natural Gas (GNG) to the surrounding environment. The Federal Railroad Administration (FRA) will analyze industry safety assessments of the proposed rail vehicles and the goal of this risk analysis is to identify and prioritize hazard scenarios so the FRA can ensure that they are properly addressed. For operational activities, a Failure Modes and Effects Analysis (FMEA) was performed to identify high risk failure modes. A modified hazard and operability study (HAZOP) methodology was used to analyze hazard scenarios for the maintenance activities for the LNG and Compressed Natural Gas (CNG) dual-fuel locomotives and the LNG tender car. Because refueling operations are highly dependent on human interactions, a human factors assessment was also performed on a sample refueling procedure to identify areas of improvement and identify best practices for analyzing future procedures.

The FMEA resulted in the identification of 87 total failure modes for the operational phase, three of which were deemed to have a High risk priority, all involving the cryogenic storage tank. The HAZOP for the LNG tender resulted in the identification of eight credible hazard scenarios and the HAZOP for the locomotive in the maintenance mode identified 27 credible hazard scenarios. The high and medium risk failure modes and hazard scenarios should be prioritized for further analysis.

Commentary by Dr. Valentin Fuster
2017;():V001T06A011. doi:10.1115/JRC2017-2281.

From the original “steam trumpet” built for locomotives in 1832 by the Leicester and Swannington Railway to modern air-pressure horns, train warning signals have not changed significantly in nearly 200 years. The effectiveness of train warning signals has been of particular concern for trespassers listening to music with headphones.

The authors have conducted research as part of a Federal Railroad Administration program to design and assess the effectiveness of candidate new emergency warning signal (EWS) sounds. This paper summarizes a literature review to understand the needs for a new EWS sound and principles of audible signal detection. Acoustic measurements were conducted of headphones to understand in-ear music levels and active and passive sound attenuation. Candidate EWS sounds were developed with a goal of maintaining the identification of a train approaching and increasing the sense of urgency and response time for trespassers to vacate the tracks. Testing of candidate EWS sounds was conducted in an audio booth and on-board a moving locomotive.

The research results have shown that a new EWS sound can maintain the association of a train approaching, increase the sense of urgency, reduce the reaction time for trespassers to vacate the tracks and improve safety on railroad corridors.

Commentary by Dr. Valentin Fuster
2017;():V001T06A012. doi:10.1115/JRC2017-2283.

Highway-rail crossing protection has perpetually been a problem for railroads and road owners. Of roughly 422,000 [1] highway-rail grade crossings in the Unites States, nearly half are passive crossings utilizing only signs and other non-active warning devices. ICrossing is a system designed to protect these passive crossings and warn motorists of approaching trains. ICrossing utilizes a system of beacons and detectors connected to a central computer. The detectors located down the track on either side of the crossing detect oncoming trains and alerts that central computer. The central computer then generates a warning message which is sent to the IBeacons that are placed on the approaches to the crossing. The beacons broadcast the generated message to the surrounding area and alert motorists to the oncoming train through a mobile application on their cell phones. This system is expected to be a cheap form of protection that can add another level of protection to many of the passive crossings located throughout the country.

Commentary by Dr. Valentin Fuster
2017;():V001T06A013. doi:10.1115/JRC2017-2288.

Highway-rail grade crossing (crossing) collisions and fatalities have been in decline, but a recent ‘plateau’ has caused the Federal Railroad Administration (FRA) to concentrate on decreasing further casualties. The Michigan Tech Rail Transportation Program has been selected to perform a large-scale study that will utilize the SHRP2 Naturalistic Driving Study (NDS) data to analyze how various crossing warning devices affect driver behavior and whether there are clear differences between the effectiveness of the warning devices.

The main results of this study are the development of a coding scheme for a visual narrative, used to validate machine vision head tracking data, and an improved baseline for the head tracking data using bivariate probability density. Head tracking data from the NDS and its correlation with coded narratives are vital to analyze driver behavior as they traverse crossings. This paper also presents preliminary results for the comparative analysis of the head tracking data from an initial test sample. Future work will extend the analysis to a larger data set, and ensure that use of the head tracking data is a viable tool for the ongoing behavior analysis work. Based on preliminary results from testing of the first data set, it is expected there will be significant positive correlation in future samples and the machine vision head tracking will prove consistent enough for use in the large scale behavioral study.

Topics: Highways , Rails
Commentary by Dr. Valentin Fuster
2017;():V001T06A014. doi:10.1115/JRC2017-2292.

Public transportation provides opportunities for people to share a common platform or mode of transportation as they move from place to place, often amassing persons in large groups or quantities. Rail transportation in particular has the benefit of accommodating very large numbers of people in one movement, often upwards of 1000 persons. The benefits to society are considerable: shared resources, lower impacts on the environment, and more efficient use of time and energy. The consequence when something goes wrong, however, can also be considerable: mass casualties (fatalities and/or injuries) from a single event, disrupted supply chains, and environmental damages to name a few. Even if persons are not physically harmed, the effects of an incident can be felt by a far greater number of persons. Adequate preparation can play a key role in minimizing the effects of mass casualty events such as railway collisions or derailments. Indeed, lives can be saved or lost depending on the resources, training, and organization that are employed when responding to a mass casualty incident.

Commentary by Dr. Valentin Fuster
2017;():V001T06A015. doi:10.1115/JRC2017-2294.

While the literature suggests that driver behavior is the main cause of most of highway-rail grade crossing crashes, it has proven to be a challenging area for research. The SHRP2 Naturalistic Driving Study (NDS) opened a window of opportunity to make a systematic analysis of the phenomenon because it includes an in-vehicle direct observation of the drivers. The first step in the analysis was the selection process of approximately 300 representative crossings for analysis from over 1,000 crossings included in the NDS. In order to allow the analysis of driver behavior in various environments, the selected set was comprised of different types of crossings. Key parameters that were considered are the types of crossings based on the installed traffic control devices, the configuration of nearby intersections, and the number of accidents that took place at the crossing in recent years. From a statistical standpoint, each group must have a size large enough to generalize the observed conclusions across other crossings with similar characteristics. In addition to NDS, resources such as the FRA accident database, the FRA crossings inventory, and Google-Maps were used in order to determine the crossings that fit the selection criteria. In future steps of the project evaluation of driver behavior over selected crossings is expected to help identify patterns that carry high risk for highway-rail crossing accidents.

Topics: Databases , Highways , Rails
Commentary by Dr. Valentin Fuster
2017;():V001T06A016. doi:10.1115/JRC2017-2304.

This paper deals with Physical Safety and Security at rail crossings. There are about 150,000 public railroad grade crossings in the U.S. Unfortunately, approximately 2,000 accidents occur every year in the U.S., resulting not only in many injuries, but also in over 200 deaths annually. The predicament is that for various reasons, people, cars, and trucks find themselves on the rail tracks of an oncoming train at a railroad crossing. The system discussed in this paper provides a relatively inexpensive Internet of Things (IoT)-based capability that can be used to alert a rail operator that there is an obstruction on the tracks, and/or possibly to interwork with (but not replace) a Positive Train Control (PTC) system thus attempting to automatically stop an incoming train. In fact, IoT is now being deployed in railroads for a variety of applications. A brief description of cybersecurity issues related to IoT deployment is also included.

Topics: Internet , Rails
Commentary by Dr. Valentin Fuster
2017;():V001T06A017. doi:10.1115/JRC2017-2327.

Rail tunnel and station smoke control system designs typically consider a fully-developed fire from a railcar as a worst case, credible fire scenario. This paper provides the results of a review and assessment of the methods used to estimate the heat release rate of a fully-developed fire inside of a railcar. The review includes large and scaled railcar testing data as well as a range of modeling techniques. Important factors affecting the railcar heat release rate are discussed along with an assessment of the current methods for estimating the railcar heat release rate.

Commentary by Dr. Valentin Fuster
2017;():V001T06A018. doi:10.1115/JRC2017-2334.

During the last decade, several Public Transportation Operators have started to test and implement technical equipment that shall detect passengers or objects intruding the clearance profile of trains in the station area. The deployed or tested systems typically supervise the track area of subways or light rails and shall stop incoming trains if an obstacle has been detected on the tracks (Guideway Intrusion Detection System, GIDS).

While some scientific and operational publications can be found in the literature for Onboard Obstacle Detection Systems and on different technical solutions for Guideway Intrusion in general, there are virtually none on planning and operations experience for Wayside GIDS in transit applications.

The paper therefore reports on the basic intention and operation of (wayside) GIDS in Unmanned and Driver Operations and findings about detection efficiency and feasibility. Some critical issues had been observed in most implementations and will be discussed in this overview paper.

TelSys GmbH has been working with researchers from TU Dresden on Video GIDS Technology in multiple installations, accumulated substantial statistics of GIDS behavior in diverse field demonstrators (Prague, Berlin, New York City, Munich) and assessed the operational results of GIDS technologies over the years. The Video GIDS is therefore introduced as an illustration example, while the considered aspects are applicable to all GIDS Technologies.

Commentary by Dr. Valentin Fuster

Energy Efficiency and Sustainability

2017;():V001T07A001. doi:10.1115/JRC2017-2217.

Diesel locomotives in heavy haul operations are good candidates to adopt energy storage systems (ESSs). This paper modelled a battery ESS and a flywheel ESS for heavy haul locomotives. Three heavy haul trains with different traction plans (diesel, diesel-flywheel, and diesel-battery) were compared. The diesel, flywheel, and battery locomotives have traction powers of 3100 kW, 2000 kW, and 3100 kW respectively. Available energy from the flywheel and battery ESSs are 500 kWh and 5000 kWh respectively. The simulated railway is about 300 km long while the trains are about 10,000 tonnes each. Traction performance and fuel consumption were compared. The results show that, compared with the diesel train, the diesel-flywheel and diesel-battery trains were 13.26% and 9.20% slower in speed respectively. However, they decreased their fuel consumptions by 12.40% and 20.65% respectively.

Commentary by Dr. Valentin Fuster
2017;():V001T07A002. doi:10.1115/JRC2017-2232.

Railways perform a significant role in the transportation system and they have relevant environmental, economic and social impacts. They are currently engineered optimizing every singular aspect rather than considering a broader system for improving the sustainability of the overall infrastructure. Thus, it is necessary to promote an effort to define a global sustainability framework for conceiving the design, construction and management of railway infrastructure. The Sustainable Rating System (SRS) proposed in this paper is a tool under development that evaluates different alternatives of railway track-bed structure. Inspired by similar efforts in the field of road engineering such as Greenroads and Greenpave, this SRS aims to be the first entirely dedicated to support railway engineers, designers and managers in taking more responsible decisions with regards to the sustainable design and maintenance of railway track-beds. It is based on a library that examines different solutions and treatments for each element of the track-bed and a table of points that assigns different scores to the different alternatives. To achieve the highest score in terms of sustainability it is necessary to maximize the points assigned to every element. In other words, the maximum score requires adopting best practices leading to more sustainable choices such as exploiting the use of recycled materials, reducing the use of non-renewable resources, the energy consumption, air pollutants and greenhouse gas emissions.

Commentary by Dr. Valentin Fuster
2017;():V001T07A003. doi:10.1115/JRC2017-2233.

Freight rail carriers have been continuously challenged to reduce costs and comply with increasingly stringent environmental standards, into a continuously competing and environmentally driven industry. In this context, current availability and relative abundance of clean and low cost non conventional gas reserves have aroused a comprehensive reevaluation of rail industry into fuel option, especially where freight rail are strongly diesel based. Countries in which rail sector is required to play an important role in transport matrix, where fuel expenditures currently accounts for a significant share of operational costs, like Australia, Brazil, United States and other continental countries, can be seen as strong candidates to adopt fuel alternatives to diesel fueled freight railways. Moreover, from an environmental perspective, the use of alternative fuels (like natural gas) for locomotive traction may allow rail freight carriers to comply with emission standards into a less technologically complex and costly way. In this context, liquefied natural gas (LNG) fueled freight locomotives are seen as a strong potential near-term driver for natural gas use in rail sector, with its intrinsic cost and environmental benefits and with the potential to revolutionize rail industry much like the transition from steam to diesel experienced into the fifties, as well as the more recent advent of use of alternating current diesel-electric locomotives. LNG rail fueled approach has been focused on both retrofitting existing locomotive diesel engines, as well as on original manufactured engines. Given the lower polluting potential of natural gas heavy engines, when compared to diesel counterparts, LNG locomotives can be used to comply with increasingly restrictive Particulate Matter (PM) and Nitrogen Oxides (NOx) emission standards with less technological complexity (engine design and aftertreatment hardware) and their intrinsic lower associated costs. Prior to commercial operation of LNG locomotives, there are some technical, operational and economic hurdles that need to be addressed, i.e. : i) locomotive engine and fuel tender car technological maturity and reliability improvement; ii) regulation improvement, basically focused on operational safety and interchange operations; iii) current and long term diesel - gas price differential, a decisive driver, and, finally, iv) LNG infrastructure requirements (fueling facilities, locomotives and tender car specifications). This work involved an extensive research into already published works to present an overview of LNG use in freight rail industry into a technical, operational and economical perspective, followed by a critical evaluation of its potential into some relevant freight rail markets, such as United States, Brazil and Australia, as well as some European non electrified rail freight lines.

Commentary by Dr. Valentin Fuster
2017;():V001T07A004. doi:10.1115/JRC2017-2241.

With the development of high-speed rail technology, the interaction between wheel and track becomes more serious, which threatens the running stability, riding quality and safety of the vehicle. Due to the selected stiffness and damping parameters, conventional passive suspensions cannot fit in with the diverse conditions of the railway. Additionally, among these vibrations contains a large amount of energy, if this vibrational energy can be recycled and used for the active suspension to control, it will be a good solution compared to the conventional passive suspensions. Many energy-harvesting shock absorbers have been proposed in recent years, the most popular design is the electromagnetic harvester including linear electromagnetic shock absorbers, rotational electromagnetic shock absorbers, the mechanical motion rectifier (MMR), and the hydraulic electromagnetic energy-regenerative shock absorber (HESA). With different energy converting mechanisms, the complicated effects of the inertia and nonlinear damping behaviors will severely impact the vehicle dynamic performance such as the ride comfort and road handling.

In the past few years, engineers and researchers have done relevant researches on HESA which have shown that it has good effects and proposed several suspension energy regeneration solutions for applying to car. This paper presents a novel application of HESA into a bogie system for railway vehicles comparing to the conventional suspension systems. HESA is composed of hydraulic cylinder, check valves, accumulators, hydraulic motor, generator, pipelines and so on. In HESA, the high-pressure oil which is produced by shock absorber reciprocation could be exported to drive the hydraulic motor, so as to drive the generator to generate electricity. In this way, HESA regenerate the mechanical vibrational energy that is otherwise dissipated by the traditional shock absorber as heat energy. Because the bogie has two sets of suspension systems, a dynamic model of bogie based on AMESim is established in order to clarify the influence of the dynamic characteristics effect and the energy harvesting efficiency when installing the HESA into different sets of the bogie. Then, set the HESA model into each suspension system of the bogie and input with the corresponding characteristic excitation, the influence of the dynamic characteristics and the energy harvesting efficiency are analyzed and compared.

The simulation results show that the system can effectively reduce the vibration of the carriage, while maintaining good potential to recycle vibratory energy. Based on the results of the simulation, the relationships as well as differences between the first suspension system and second suspension system have been concluded, which are useful for the design of HESA-Bogie. Moreover, comparing the energy harvesting efficiency discrepancy between the two suspension systems, the potential of energy harvesting of a novel railway vehicle bogie system with HESA has been evaluated and then the best application department has been found, which indicates the theoretical feasibilities of the HESA-bogie to improve the fuel economy.

Commentary by Dr. Valentin Fuster
2017;():V001T07A005. doi:10.1115/JRC2017-2263.

With the increasing of the train load, the wheel-rail wear is worsening, the maintaining and replacing cycle is shortened enormously, the problem of replacing steel rail and wheel prematurely not only make the railway transportation cost increasing, but also affect the railway normal transportation. This paper proposes a novel type of active energy self-supply radial steering technology — the parallel interconnection hydraulic-electric energy-harvesting active radial steering bogie system. This system is a typical “machine – electric – hydraulic” coupling system, which includes parallel interconnection hydraulic-electric energy-harvesting suspension and active radial steering bogie, consisting of mechanical, electronic, hydraulic and control subsystems internally. In this system, the radial steering bogie is equipped with four HESA, and HESA can reuse the mechanical vibration energy which used to be transformed into waste heat by the shock absorber. In this system, the mechanical vibration energy is now used to drive power module of active radial steering bogie, so as to implement the train’s active radial steering without external power supply. This paper discusses the evolution of radial steering bogie in general, and introduces the structure and basic principle of the parallel interconnection electro-hydraulic energy-harvesting active radial steering bogie system. The system establishes a model of the parallel interconnection hydraulic-electric energy-harvesting shock absorber. The typical vertical irregularity of American track is established. In the paper, we research on the system’s damping performance and energy recovery performance through stimulation. Simulation results show that the maximum vertical acceleration of train body is reduced from 42.9% to 62.3%, and the average energy recovery power from the system increases from 217W to 1835W when the system works at the six levels of track irregularities.

Commentary by Dr. Valentin Fuster
2017;():V001T07A006. doi:10.1115/JRC2017-2303.

Transportation industry at large is a major consumer of fossil fuels and contributes heavily to the global greenhouse gas emissions. A significant portion of these emissions come from freight transportation and decisions on mode/route may affect the overall scale of emissions from a specific movement. It is common to consider several alternatives for a new freight activity and compare the alternatives from economic perspective. However, there is a growing emphasis for adding emissions to this evaluation process. One of the approaches to do this is through Life Cycle Assessment (LCA); a method for estimating the emissions, energy consumption and environmental impacts of the project throughout its life cycle.

Since modal/route selections are often investigated early in the planning stage of the project, availability of data and resources for analysis may become a challenge for completing a detailed LCA on alternatives. This research builds on such detailed LCA comparison performed on a previous case study by Kalluri et al. (2016), but it also investigates whether a simplified LCA process that only includes emissions from operations phase could be used as a less resource intensive option for the analysis while still providing relevant outcomes. The detailed LCA is performed using SimaPro software and simplified LCA is performed using GREET 2016 model. The results are obtained in terms of Kg CO2 equivalents of GHG emissions. This paper introduces both detailed and simplified methodologies and applies them to a case study of a nickel and copper mine in the Upper Peninsula of Michigan. The analysis’ are done for three modal alternatives (two truck routes and one rail route) and for multiple mine lives.

Commentary by Dr. Valentin Fuster


2017;():V001T09A001. doi:10.1115/JRC2017-2201.

EMC/EMI is a source of concern from the beginning of planning a new railway line. High powered electrified railways such as HSR are usually AC electrified. This poses a hazard for nearby systems and users. Induced voltages can create electric shock risks or malfunction in signalling or other nearby systems. LRTs, metro lines or commuter systems are usually DC fed and can be located near electromagnetic sensitive equipment such as MRI equipment in hospitals or research equipment — such as electron microscopes — in campuses or laboratories. EMF calculation and impact assessment in early phases of the project rely on simulation and expertise in these complex multi system interrelations. Rail traction creates EM fields which tend to decrease rapidly as the distance from the track axis increases. However, considerations about passengers, workforce and public safety and system compatibility are always needed. As an example, transient currents in DC rail, especially due to short circuits or arcs can interfere with nearby equipment. Even semi steady state DC currents associated with normal operation of the line (traction and breaking currents) present EMC related hazards that need to be assessed in order to evaluate if mitigation measures for associated risks are needed. AECOM’s Madrid Transportation Design Center has developed a tool that provides 3D EMF calculations for railway lines, either AC or DC. This tool, called EMFRail, can deliver EMF estimations based on power load supply simulations considering alignment, separation between tracks, geometry of the electrification system (OCS, third rail), rolling stock mechanical and electric features as well as regenerative braking in order to provide decision support information to make educated project decisions from the beginning of the design. Regenerative braking is a common energy saving tool for railways these days, but has posed new EMF hazards since currents sent back to the OCS can be bigger than those related to traction and this process can occur in different locations of the line (usually when the train is decelerating from maximum speed). This tool can calculate both magnetic and electrical fields for traction frequencies. This tool has been used in several LRT and rail projects providing insightful information to adopt mitigation measures such as underground feeders or operational limitations. EMFRail can simulate mitigation measures for challenging situations such as EMF caused by semi steady state maximum currents (prior to the trip of protection systems). EMFRail can also provide EMF calculations for transmission or distribution power lines once the required current or voltage values (module and phase) are known as well as the position of the different conductors (OCS wires, feeders, rails) of the line under study. EMFRail is developed using MatLab programming suite taking advantage of matrix operation capabilities. Output results are isocurves that can be superimposed to a raised view drawing, 3D contours for specific magnetic field values or even time animated frames to understand worst case scenarios that sometimes are not easy to foresee based on common assumptions.

Commentary by Dr. Valentin Fuster
2017;():V001T09A002. doi:10.1115/JRC2017-2207.

Since the introduction of electrified transit systems in the United States there has been a number of advancements in the field of corrosion control related to light rail transit (LRT) systems. Modern day direct current (dc) powered LRT systems have been designed with a variety of corrosion control features built-in.

Most of the research into corrosion control and the mitigation of stray currents known as electrolysis in the early days of electrified transit systems first appeared extensively in papers prepared and presented by personnel of the National Bureau of Standards. This research has led to better protection against corrosion of transit systems and nearby structures throughout the years.

Due to the ever increasing number of transit systems being built or upgraded, it’s essential to incorporate the installation, testing and monitoring of corrosion control measures in these transit systems. By integrating these corrosion control features into the design of LRT systems and subsystems, it will help to prevent premature corrosion failures on LRT fixed facilities and other structures. This paper identifies the main causes of corrosion and how corrosion control can be implemented into the design of LRT systems to prevent damage to the transit system and other structures.

Commentary by Dr. Valentin Fuster
2017;():V001T09A003. doi:10.1115/JRC2017-2224.

In today’s Swedish and Norwegian low frequency railway power system the voltage at a converter is controlled such that its voltage will drop with increased reactive power output. However, for low frequency railways the influence of active power on voltage is larger compared to public power systems and alternative methods are interesting to investigate.

This paper presents a modified voltage control law for increased load sharing between converter stations and reduce the risk for converter overload in low frequency railways power systems. The modified voltage control law is derived mathematically and tested with different droops for two case studies. The results confirms the increased load sharing between the converter stations.

The results are analysed and discussed; ideas are presented to counteract some of the negative impacts of the modified voltage control law.

Commentary by Dr. Valentin Fuster
2017;():V001T09A004. doi:10.1115/JRC2017-2258.

In present-day railway power supply systems using an AC frequency lower than the one in the public power system of 50/60 Hz, high voltage overhead transmission lines are used as one measure of strengthening the railway power supply system grids. This option may be economically beneficial, compared to strengthening the grid purely by increasing the density of converter stations or increasing the cross section areas of the overhead catenary wires.

High voltage AC transmission lines in the railway power supply system allow larger distances between converter stations than would otherwise be possible for a given amount of train traffic. Moreover, the introduction of AC transmission lines implies reduced line losses and reduced voltage level fluctuations at the catenary for a given amount of train traffic.

However, due to the increased public and government resistance for additional overhead high voltage AC transmission lines in general, different alternatives will be needed for the future improvements and strengthening of railway power systems. For a more sustainable transport sector, the share and amount of railway traffic needs to increase, in which case such a strengthening becomes inevitable.

Earlier, usage of VSC-HVDC transmission cables has been proposed as one alternative to overhead AC transmission lines. One of the main benefits with VSC-HVDC transmission is that control of power flows in the railway power systems is easier and that less converter capacity may be needed. Technically, VSC-HVDC transmission for railway power systems is a competitive solution as it offers a large variety of control options. However, there might be other more economical alternatives reducing the overall impedance in the railway power system.

In public power systems with the frequency of 50/60 Hz, an excess of reactive power production in lowly utilized cables imposes an obstacle in replacing overhead transmission lines with cables. In low frequency AC railway power system, the capacitive properties are less significant allowing longer cables compared to 50/60 Hz power systems. Moreover, in converter-fed railways, some kind of reactive compensation will automatically be applied during low-load. At each converter station, voltage control is already present following the railway operation tradition.

Therefore, in this paper, we propose AC cables as a measure of strengthening low-frequency AC railway power systems. The paper compares the electrical performances of two alternative reinforcement cable solutions with the base case of no reinforcement. The options of disconnecting or toggling the cables at low load as well as the automatic reactive compensation by converter voltage control are considered. Losses and voltage levels are compared for the different solutions. Investment costs and other relevant issues are discussed.

Commentary by Dr. Valentin Fuster
2017;():V001T09A005. doi:10.1115/JRC2017-2270.

In this paper we present the follow-up of our work on the assessment of pantograph arcs during loss-of-contact transients. It is not easy to accurately detect the gap between the contact strip of the pantograph and the contact wire on the fly. Instead, in the European Standards EN50119 the measurable arcs are used in the performance criteria. This paper addresses the issue of arc detection from two aspects: arc image and arc intensity. Using the arc intensity sensors and an action camera we performed two field tests to verify the speculation that arc intensity does vary in different directions. This implies the requirement of more than one sensor in the detection of arcs, and the need to combine the outputs of all sensors to obtain an effective measure of arc intensity. Both issues are addressed in this paper using video clips and measurement data conducted in a field test in Taiwan.

Commentary by Dr. Valentin Fuster
2017;():V001T09A006. doi:10.1115/JRC2017-2290.

Several Authorities are procuring Hybrid Streetcars with OESS. The energy storage system needs to be protected from ground faults, external and internal to the vehicle. A Hybrid Streetcar has an OESS consisting of either Lithium Batteries or super capacitors, with an OESS converter connected to, or integrated with, the Traction Inverter. During a ground fault of the high voltage circuit, the freewheeling diode in an OESS charger creates a fault path between the energy storage elements and ground.

Typical vehicle designs use a fuse for catastrophic protection, depending on the vehicle ground fault scheme for detection and protection. The vehicle’s primary ground fault detection device is an HSCB, usually connected between the shop switch and traction inverter; the auxiliary inverter is typically protected using a fuse. An HSCB is able to protect typical fault currents seen within the traction chain, but is not designed for OESS fault currents. If a fault occurs the fuse for the catastrophic protection of the OESS will blow before the HSCB will trip, potentially damaging equipment, making the vehicle inoperable. This paper compares alternative methods which can be deployed to detect and protect the OESS from a ground fault.

Commentary by Dr. Valentin Fuster
2017;():V001T09A007. doi:10.1115/JRC2017-2319.

Metrolinx, Toronto’s rail authority currently has 200 engineering projects underway with a value of $16 billion. One of the largest projects is a $4 billion Electrification Project for the Toronto commuter rail lines. In support of the engineering design of the project, in November of 2015 Tulloch Engineering was contracted to provide a complete engineering survey of six Metrolinx railway commuter corridors originating from Union Station in Toronto, Canada. Tulloch used a unique combination of mobile LiDAR, static LiDAR, and conventional infill ground survey to complete the project. LiDAR, which stands for Light Detection and Ranging, is a surveying method that measures distance to a target by illuminating that target with a laser light. Using LiDAR technology provided significant advantages to the Electrification Project over using convention ground survey techniques.

Metrolinx is a Canadian crown corporation responsible for the Greater Toronto and Hamilton Area’s GO Transit rail and bus commuter system. GO Transit trains currently carry 190,000 commuters per day. Electrification of Metrolinx GO Transit rail commuter rail corridors requires the upgrading of infrastructure and providing a means of getting the electricity to the trains which includes new electrical substations, overhead power lines and new equipment. The electrification is part of the GO Regional Express Rail program, which will expand the capacity of the GO rail network to provide customers with faster, more frequent and more convenient service to and from dozens of stations in core sections of the GO rail network throughout the day, evenings and weekends. Electrification is planned for most of Metrolinx commuter rail corridors by 2022–2024. The engineering technical and program management consultant for the Electrification Project is Gannett Fleming.

An initial requirement for Metrolinx Electrification project is an up to date engineering survey to enable the preliminary engineering design. Our survey project involves surveying approximately 170 miles of railway corridor for 6 GO Transit tracks originating from Union Station in downtown Toronto. Our mobile LiDAR survey system was mounted on a GO Transit hi-rail truck; with most of the surveying occurring at night due to the heavy train traffic and since LiDAR is an active sensor.

Tulloch provided a unique hybrid surveying approach, using mobile LiDAR surveying to collect all the visible features in the corridor, followed by conventional ground surveys to fill in missing features obscured from the LiDAR system’s field of view and static LiDAR surveys for some of the bridges inaccessible with mobile LiDAR. This is the first time Metrolinx has contracted an engineering survey using these multiple survey technologies. This survey approach reduces delivery timelines, limits track disruptions, and greatly improves safety. A major advantage of mobile LiDAR surveying for the GO-Transit rail corridors is that collection can occur at night when train activity is low and in a fraction of the time it takes to survey using conventional ground crews. This enabled project schedules to be advanced, as base mapping was completed in about 60% of the normal time required for the engineering survey. Using mobile scanning on the tracks reduced safety risks associated with on track field surveys. In addition, the resultant LiDAR point cloud can be revisited in the office, and additional features and critical information picked up without having to send field crews back to do so. The homogeneous nature of the point cloud, combined with the conventional in-fill survey provides a rich, full feature data set that can be used at various stages in the engineering design process.

Commentary by Dr. Valentin Fuster

Vehicle Track Interaction

2017;():V001T10A001. doi:10.1115/JRC2017-2216.

According to the structural characteristics of the double-block track, using the Green’s function and superposition principle, the analytical model of the vertical vibration of the double-block track in frequency domain was established to analyze the responses of the double-block track in frequency domain and the influences of fastener stiffness, bedplate thickness and subgrade supporting stiffness on it. The results show that there are three obvious peaks for the rail mobility which are caused by bedplate resonance (35 Hz), rail resonance (200 Hz) and pinned-pinned resonance (1 kHz). Within the frequency range of less than 35 Hz, the bedplate mobility is determined by the bedplate supporting stiffness. Also the bedplate vibration decay rate increases with the increasing frequency. The bedplate resonance and wheel-rail coupling resonance have the most significant effect on the bedplate displacement. The frequency range where the rail high vibration decay rate lies gets wider with the larger fastener stiffness. Increasing the bedplate mass cannot attenuate its vibration in the mid-high frequency range.

Topics: Vibration
Commentary by Dr. Valentin Fuster
2017;():V001T10A002. doi:10.1115/JRC2017-2221.

Locomotive traction studies have been extensively performed in multi-body software packages. Generally, these research activities have been focused on purely mechanical system design issues and, as a result, there is a limited amount of information available on modeling locomotives under the influence of traction/braking capabilities and train dynamics. Evidence of using results from longitudinal train dynamics simulations as input to locomotive dynamics simulations has also been limited and information on this is rarely presented in the public domain. This means that locomotive traction/braking studies are commonly focused on the dynamics of an individual locomotive and are limited in terms of implementation of intrain forces. Recent progress shows some activities involving the application of approximations of lateral coupler forces to replicate a locomotive’s dynamics on the track. However, such an approach has its own limitations and does not fully depict the real behavior of locomotives. At this stage, the optimal technique capable of covering all locomotive behavior issues when traveling in a train configuration is to use a co-simulation approach between a multibody software package and a train dynamics code. This paper describes a methodology for the development of such a technique and presents numerical experiments for locomotive dynamics studies. The results obtained from co-simulation runs for three heavy haul locomotives in a head-end consist, taking into account in-train forces and speeds, are discussed along with limitations found during the development process.

Commentary by Dr. Valentin Fuster
2017;():V001T10A003. doi:10.1115/JRC2017-2222.

The traction performance of a locomotive under real operational conditions is strongly dependent on friction conditions present at the wheel-rail interface. The tribology of the contact process changes during the locomotive running process and the conditions are not ideal due to the presence of a third body layer between wheels and rails. This leads to the complexities of the non-linear wheel-rail contact. To describe this system correctly, the real working conditions need to be known. The exact conditions are both complex and vary with location because of the potential presence of additional contamination material. The realization of high adhesion under traction or braking assumes that a locomotive produces a high slip that removes some of the third body material in the contact and this effect leads to an increase in values of friction coefficient from the leading to each subsequent following wheel on each side of the bogie. The resulting friction change can improve the tractive effort of a locomotive that is a key issue for railway operations. In this paper, the change of friction coefficients under traction are investigated by means of engineering analysis and some assumptions have been stated to generate input parameters for wheel-rail contact modelling in order to understand the influence of this rail cleaning process on locomotive dynamics. The assumptions made allow adopting a progressive increase of friction coefficient under an analytical assumption for each wheel. The multibody model of a high adhesion locomotive that includes a traction system has been developed in a specialized multibody software. The results obtained show the changes in dynamic behavior of a locomotive and indicate the influence on traction performance.

Topics: Locomotives , Rails
Commentary by Dr. Valentin Fuster
2017;():V001T10A004. doi:10.1115/JRC2017-2302.

Advanced active suspension systems has attracted considerable attention in modern railway vehicle designs in recent years. The purpose of the suspension is to attenuate the vehicle vibrations due to various rail excitations. With active suspensions it is aimed to improve the performance in some cases, while not making it worse in others. The performance-related objectives can be approximately translated in different norm bounds on certain transfer functions or impulse responses.

In this paper, a multi-objective problem is formulated as a non-convex and non-smooth optimization problem for a full-car railway vehicle modelled with seventeen-degrees-of-freedom (17 DOF) and excited by random rail inputs. The controller order restricted to be less than or equal to the passive system model order. For a range of orders, controllers are synthesized by using the HIFOO toolbox.

Commentary by Dr. Valentin Fuster

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