A review of past accident data shows that several fatalities have been attributed to passenger ejection through window openings during passenger train accidents. To study and address this issue, literature review and accident analyses were performed to investigate the safety aspects of passenger rail window glazing. A common failure mode is when the external gaskets that hold the glazing pane in place shear off and the windows are pushed inside the carbody during rollover derailments. This leads to passengers being ejected, often fatally, out of the train. Passenger containment was identified as the main improvement to be made to glazing systems. New or updated retention methods are thought to be necessary in the pursuit of safety. Considering feasibility, implementation time, likelihood of success, and the potential for retrofit, a few concepts including various methods of zip-strip protection, a revised zip-strip location, and recessed window glazing have been ideated and the top rated concepts are being developed further. In the next phase of work, field tests and additional analyses will help determine the efficacy of the proposed solutions and the necessity for additional engineering design requirements.

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.

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 equipped 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. This paper describes the results of the coupling tests of conventional equipment. In this set of tests, a moving locomotive was coupled to a standing cab car. The coupling speed for the first test was 2 mph, the second test 4 mph, and the tests continued with the speed incrementing by 2 mph until the last test was conducted at 12 mph. The damage observed resulting from the coupling tests is described. The lowest coupling speed at which damage occurred was 6 mph. Prior to the tests, a one-dimensional lumped-mass model was developed for predicting the longitudinal forces acting on the equipment and couplers. The model predicted that damage would occur for coupling speeds between 6 and 8 mph. The results of these conventional coupling tests compare favorably with pre-test predictions. Next steps in the research program, including future full-scale dynamic tests, are discussed.

Research to facilitate industry efforts to safely use natural gas as a locomotive fuel is being directed by the Federal Railroad Administration’s (FRA’s) Office of Research, Development, and Technology. This research is being conducted cooperatively with the Association of American Railroads (AAR). The research results are being shared with the AAR’s Natural Gas Fuel Tender Technical Advisory Group (NGFT TAG), which includes AAR, Member Railroads, and FRA, with support from ARA and Volpe Center. The NGFT TAG is developing industry requirements, including crashworthiness requirements, for revenue-service natural gas fuel tenders. Five accident scenarios have been drafted by the NGFT TAG: a train-to-train collision, a grade-crossing collision, rollover, shell impact, and head impact. Each scenario includes a description of the equipment, the impact conditions, and the prescribed outcome. Conceptually, these tender scenarios parallel the scenarios described in 49 CFR Part 229 Appendix E for locomotive crashworthiness. The focus of the NGFT TAG discussions has expanded to include alternative static requirements. Conceptually, the tender static requirements parallel the requirements for locomotive crashworthiness in AAR S-580. Requirements in S-580 for locomotive structure include static load capacities, material properties, and material thicknesses. For conventionally-designed locomotives, meeting the static requirements of S-580 is accepted as meeting the dynamic requirements of Appendix E. The tender static requirements under development are intended to provide the same level of crashworthiness as the previously proposed dynamic requirements. The primary advantage of static crashworthiness requirements is that compliance can be shown with classical closed-form engineering analyses. A disadvantage is that design features are presumed, such as the inclusion and location of collision posts in a conventional locomotive design. Design features are not presumed in dynamic crashworthiness requirements; however, compliance must be shown with a design-specific validated computer simulation model. So while dynamic requirements allow for a wide range of design approaches, showing compliance often requires extensive effort. This paper focuses on technical information to help support development of alternative static requirements for the train-to-train collision scenario. The goal of the static requirements is to provide the same level of crashworthiness as the dynamic requirements under discussion by the NGFT TAG. Tender features capable of providing the desired level of performance are proposed. These features have been selected such that a tender with these features would be crashworthy-compatible with a wide range of new and existing locomotive structural designs.

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. The 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. It has been shown analytically that push back coupler trigger loads exceed the service load capacity of conventional couplers and draft gears. Two sets of coupling tests are planned to demonstrate this, one with a locomotive equipped with conventional draft gear and coupler and another with a locomotive equipped with a pushback coupler. These tests allow for comparison of conventional with CEM-equipped locomotive measured performance during coupling. In addition to the coupling tests, car-to-car compatibility tests of equipped locomotives and 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. In the coupling tests of conventional equipment, the maximum coupling speed for which there is no damage to either vehicle will be measured. A moving locomotive will be coupled to a standing cab car. The coupling speed for the first test will be 2 mph, the second test 4 mph, and the tests will continue with the speed incrementing by 2 mph until damage occurs to either vehicle. This paper describes the test requirements and analysis predictions for the coupling tests of conventional equipment. The equipment to be tested, track conditions, test procedures, and measurements to be made are described. A one-dimensional model for predicting the longitudinal forces acting on the equipment and couplers has been developed, along with preliminary predictions for the conventional coupling tests. It is expected that damage will occur for coupling speeds between 6 and 8 mph.

Twenty-three commuter and inter-city passenger train accidents, which occurred over the past twenty years, have been analyzed. The analysis has assessed the potential effectiveness of various injury mitigation strategies. The strategies with the greatest potential to increase passenger safety are interior occupant protection, coupler integrity, end structure integrity, side structure integrity, and glazing system integrity. We recommend that these strategies be researched further. Three types of accidents were analyzed: train-to-train collisions, derailments, and grade-crossing collisions. Train-to-train collisions include the commuter train-freight train collision in Chatsworth, California on September 12, 2008. In Chatsworth a commuter train collided with a freight train at a closing speed of ∼80 mph, fatally injuring twenty-five people and injuring more than 100 others. Derailments include the commuter train derailment in Spuyten Duyvil, New York on December 1, 2013, fatally injuring four people and injuring more than fifty others. Grade-crossing accidents include the commuter-SUV collision in Valhalla, New York on February 3, 2015, which resulted in six fatally injured people, including the SUV driver, and thirteen severely injured people. Four categories of mitigation strategies were considered: train crashworthiness, wayside structure crashworthiness, fire safety, and emergency preparedness. Within each of these categories are equipment features, which may potentially be modified to further mitigate injuries. The features are simple noun phrases, e.g., “floor strength,” implying that the floor strength should be increased. Train crashworthiness includes features such as end strength, floor strength, coupler separation, and numerous others. Wayside structure crashworthiness includes features such as frangible catenary poles and third rail end caps. Fire safety includes train interior and train exterior features for minimizing the potential for fire and for reducing the rate at which fire might spread. Emergency preparedness includes features for emergency egress, access, lighting, signage, and on-board equipment, such as fire extinguishers. Overall, rail passenger travel has a high level of safety, and passenger train accidents are rare events. The numbers are low for expected casualties per passenger-mile and casualties per passenger-trip. A high level of safety, however, does not mean efforts to improve it should cease. But it does mean that crashes are rare events. Rare events in complex systems are notoriously difficult to analyze with confidence. There are too few accidents to provide the data needed for even a moderate degree of mathematical confidence in statistical analysis. Analyses of similar data in medical and scientific fields have been shown to be prone to the biases of the researchers, sometimes in subtle and difficult-to-detect ways. As a means of coping with the sparse data and potential biases, the goal has been to evaluate the accidents transparently and comprehensively. This approach allows a wide audience to understand how injuries and fatalities occur in passenger train accidents and, most importantly, allows us to prioritize mitigation strategies for research.

Research is being conducted to develop technical information needed to formulate effective natural gas fuel tender crashworthiness standards. This research is being performed for the Federal Railroad Administration’s (FRA’s) Office of Research, Development, and Technology, and intended to facilitate industry efforts to use natural gas as a locomotive fuel. Strategies to assure crashworthiness during moderate accidents, such as train-to-train collisions at speeds up to 40 mph, are being evaluated. This research applies the approach FRA has used to develop technical information on locomotive, hazmat tank car, and diesel fuel tank crashworthiness. There are four primary tasks: 1. Definition of collision scenarios 2. Evaluation of traditional designs 3. Evaluation of alternative designs 4. Recommendation of effective crashworthiness strategies The tender scenarios have been drafted from reviews of freight train accidents and of scenarios developed for locomotives, hazmat tank cars, and fuel tanks. From these reviews, five scenarios were selected. These scenarios are intended to bound the range of collisions that a tender may experience, are being used to evaluate the crashworthiness of traditional tender designs, and will be used to evaluate alternative design tenders. The five candidate scenarios are: 1. Train-to-train collision 2. Grade-crossing accident 3. Tender derailment and rollover 4. Impact into tender tank shell during derailment 5. Impact into tender tank head during derailment As part of previous research on locomotives and passenger equipment, a range of crashworthiness analysis techniques were developed. These include simplified techniques, which can be performed rapidly and provide essential results, and detailed computer simulations which provide a wealth of information. The crashworthiness performance of a hypothetical tender design has been evaluated using simplified techniques. Simplified techniques include quasi-static crush analysis of structural elements and lumped-parameter analysis of train dynamics. The results suggest that efforts to enhance crashworthiness should principally be directed toward the train-to-train scenario. Work is ongoing to develop strategies for improving tender crashworthiness. This research is being conducted cooperatively with the Association of American Railroads (AAR). The research results are being shared with the AAR’s Natural Gas Fuel Tender Technical Advisory Group (NGFT TAG). The NGFT TAG is developing industry standards, including crashworthiness requirements, for revenue-service natural gas fuel tenders. There is a companion paper which describes crashworthiness research sponsored by AAR, including detailed computer simulations of tender crashworthiness. This paper describes development of scenarios and simplified analyses of tender crashworthiness.

The Federal Railroad Administration’s (FRA) Office of Research and Development is conducting research into the occupied volume integrity (OVI) of passenger railcars. OVI refers to a passenger railcar’s ability to preserve space for passengers and crew during accident loading conditions. The information developed in this research program will form the basis for establishing alternative OVI evaluation procedures. These alternative procedures, in turn, will allow a wider variety of passenger railcar designs to have their OVI evaluated, will provide guidance for applying modern engineering technologies, such as finite element analysis (FEA), and will continue to ensure a level of safety in evaluated vehicles equivalent to conventional evaluation. As part of this research program, two tests and corresponding FEA were conducted on a Budd M-1 passenger railcar that had been retrofitted with crash energy management (CEM) components on both ends. This testing and analysis program was sponsored by FRA and carried out by Transportation Technology Center, Inc. (TTCI), Arup, and the Volpe Center. An 800,000 pound load test was conducted on March 13, 2013 and was intended to elastically deform the car. The data generated during this test were, in turn, used to validate FE models of the M-1 car. The second test was performed on July 17, 2013. This test introduced loads into the occupant volume through its CEM attachment points until the ultimate, or crippling, load was reached. By loading the occupant volume through the CEM components, the test load path is similar to the load path that would be traveled by collision loads during activation of the CEM system. This paper presents the results of the crippling test, discusses the sequence of buckling that was observed to occur in the test, and compares the results of the test with the results from FEA of the test conditions. During the crippling test, the car exhibited a crippling load of 1.1 million pounds. This value is consistent with crippling loads reached by two Budd Pioneer cars that were previously tested in an FRA program. The buckling sequence of the members making up the M-1’s occupant volume were particularly well-captured by strain gages during this most recent test. The load path through the occupant volume and the sequence of progressive buckling of structural members is discussed. Additionally, the presence of existing damage and previously-repaired areas and their likely effects on the crippling behavior of the car are discussed.

The Federal Railroad Administration has conducted a number of detailed investigations of passenger train accidents which result in fatal injuries and/or multiple serious injuries. The objective of these investigations is to reconstruct the sequence of events and to determine the causal mechanisms for injuries and fatalities. This paper presents a reconstruction of the sequence of events and the train collision dynamics results for three accidents: - the passenger train to freight train collision with a closing speed of 80 mph in Chatsworth, California on September 12, 2008; - the passenger train to freight train collision with a closing speed of 33 mph in Chicago, Illinois on November 30, 2007; - the passenger train to freight car collision with a closing speed of 23 mph in Canton, Massachusetts on March 25, 2008. The reconstructions are developed from information gathered during field investigations of occupant injury (via interview and reports), damage to the interior fixtures, structural damage to the equipment, and wayside damage. Engineering analyses are then conducted to integrate the data gathered during the field investigation, including train collision dynamics modeling which estimates the gross motions of each of the rail cars during the collision. To assure that the model reasonably captures the collision dynamics, model results are first compared with the post-accident equipment damage information gathered in the investigations. The model is then used to estimate the severity of the decelerations experienced by the occupants. The Secondary Impact Velocity (SIV) provides an indication of severity of the interior environment experienced by the passengers and crew during the accident. In a companion paper, the SIVs are correlated with the observed level of damage to the interior seats and fixtures. The selected accidents represent a range of collision conditions, with closing speeds from 23 to 80 mph, single- and multi-level passenger cars, and colliding freight equipment from a long train to a single car. The selected accidents are similar in that in all cases the passenger trains are locomotive-led. The differences in collision speed and mass of the colliding equipment resulted in substantial differences in the observed damage to the equipment as well as differences in the estimated SIVs. These differences are discussed in the paper.

The Office of Research and Development of the Federal Railroad Administration conducts engineering research to address protection of passengers and crew during train accidents. This research includes accident investigations and dynamic seat testing to assess occupant injury during simulated accident conditions. Observations from selected accident investigations are compared with dynamic seat test results, based on the requirements in the Standard for Passenger Seats in Passenger Rail Cars, APTA-SS-C&S-99-016 [1], referred to simply as the Seat Standard. The Seat Standard requires sled testing of rail passenger seats to demonstrate that seats provide a minimum level of crashworthiness in the event of an accident. The interior crashworthiness comparisons between accidents and seat tests are based on the deceleration time history (crash pulse), damage to seats and/or tables, injury type and severity, and occupant kinematics. These comparisons have been made to assess the degree to which current test practice produces injury measurements and interior fixture damage that are consistent with the injuries and equipment damage observed in accidents. When test results and accident observations do not compare well, revisions to the prescribed test conditions may be warranted. The following three accidents have been selected for comparison in this paper. They were selected from accident investigations in which the Volpe National Transportation Systems Center participated, the amount of relevant data collected during the investigation, and the dynamic seat test data that was available for comparison of the specific type of seats or tables involved in the accidents. The accidents represent a range of accident speeds, type of equipment, and collision severity: - passenger train to freight train collision with a closing speed of 80 mph in Chatsworth, California, on September 12, 2008 [2]; - passenger train to freight train collision with a closing speed of 33 mph in Chicago, Illinois, on November 30, 2007 [3, 4]; - passenger train to freight car collision with a closing speed of 23 mph in Canton, Massachusetts, on March 25, 2008. A companion paper provides detail on the structural crashworthiness of the cars in the same three accidents, and describes the computer models that were developed to estimate the crash pulse, or acceleration-time history, for each rail car in the accidents [5].

This research program was sponsored by the Federal Railroad Administration (FRA) Office of Research and Development in support of the advancement of improved safety standards for passenger rail vehicles. FRA and the Volpe National Transportation Systems Center (Volpe Center) have conducted a research program to develop alternative methods for demonstrating occupied volume integrity (OVI) of passenger rail cars using a combination of testing and analysis. Previous publications have addressed the planning and progress of a series of tests intended to examine the collision load path through the occupant volume of passenger cars equipped with crash energy management (CEM) systems. This program has included an elastic 800-kip buff strength test, two quasi-static tests that loaded a passenger car to its ultimate (crippling) capacity, and corresponding finite element (FE) analyses of each test. This paper discusses the two crippling tests and the companion FE analyses. One alternative method for evaluating OVI moves the applied loads from the line of draft to the collision load path. This alternative methodology also permits a combination of testing and analysis to be used to demonstrate the car’s OVI, in contrast to the conventional methodology (as prescribed in existing FRA regulations) which only permits testing. The alternative methodology was adopted as the recommendations developed by the Railroad Safety Advisory Committee’s (RSAC) Engineering Task Force (ETF) in its “Technical Criteria and Procedures for Evaluating the Crashworthiness and Occupant Protection Performance of Alternatively-Designed Passenger Rail Equipment for Use in Tier I Service.” The research program was undertaken to verify the efficacy of using a combination of elastic testing and plastic analysis to evaluate the OVI of a passenger car loaded along its collision load path as prescribed in the ETF report. Earlier in this research program an elastic test of a Budd Pioneer car was used to validate an FE model of the car, per the ETF’s procedures. This model was then modified to reflect the condition of the car in its crippling test configuration. The model was used to simulate the crippling behavior of the car, following the ETF’s procedures. Two Pioneer cars were then tested to crippling to provide additional data to validate the FE model and the proposed alternative OVI evaluation. Because the test cars used in this research program were equipped with CEM systems, the alternative evaluation loads were placed at the locations where the energy-absorbing components attached to the occupant volume. During both crippling tests, loads were measured at each energy-absorber support location on the live and restrained ends of the car. Additional instrumentation used in the second crippling test included strain gages on the major longitudinal structural members, displacement transducers at each load location, and vertical, lateral, and longitudinal displacement transducers on the underframe of the car. The results of the FE analysis compare favorably with the results of the crippling tests. In particular, the crippling loads are consistent between the tests and analysis: crippling loads for the first and second cars tested were 1.15 and 1.19 million pounds respectively, and the pre-test FEA estimated a crippling load of 1.19 million pounds. The research program has established a technical basis for the alternative OVI requirements and methodology.

The Office of Research and Development of the Federal Railroad Administration (FRA) and the Volpe Center have been conducting research into developing an alternative method of demonstrating the occupied volume integrity (OVI) of passenger rail equipment through a combination of testing and analysis. This research has been performed as a part of FRA Office of Research and Development’s Railroad Safety Research and Development program, which provides technical data to support safety rulemaking and enforcement programs of the FRA Office of Railroad Safety. Previous works have been published on a series of full-scale, quasi-static tests intended to examine the load path through the occupant volume of conventional passenger cars retrofitted with crash energy management (CEM) systems. This paper reports on the most recent testing and analysis results. Before performing any tests of proposed alternative loading techniques, an elastic test of the passenger car under study was conducted. The elastic test served both to aid in validating the finite element (FE) model and to verify the suitability of the test car to further loading. In January, 2011, an 800,000 pound conventional buff strength test was performed on Budd Pioneer 244. This test featured arrays of vertical, lateral, and longitudinal displacement transducers to better distinguish between the deformation modes and rigid body motions of the passenger car. Pre-test car repairs included straightening a dent in one side sill and installing patches over cracks found in the side sills. Additionally, lateral restraints were added to the test frame due to concerns in previous tests associated with lateral shift in the frame. As a part of this testing program, a future test of a passenger car is planned to examine an alternative load path through the occupied volume. In the case of Pioneer 244, this load path places load on the floor and roof energy absorber support structures. Loading the occupant volume in this manner more closely simulates the loading the car would experience during a collision. FE analysis was used in conjunction with full-scale testing in this research effort. An FE model of the Pioneer car was constructed and the 800-kip test was analyzed. The 800-kip test results were then compared to the analysis results and the model was adjusted post-test so that satisfactory agreement was reached between the test and the model. In particular, the boundary conditions at the loading and reaction locations required careful attention to appropriately simulate the support conditions in the test. Because the 800-kip load was applied at the line of draft, this test results in significant bending as well as axial load on the car. To ensure that both the axial and bending behaviors are captured in the model, the key results that were compared between test and model are the longitudinal force-displacement behavior and the vertical deflections at various points along the car. The post-test model exhibited good agreement with the compared test results. The validated model will be used to examine the behavior of the occupant volume when loaded along the alternative load path.

The Volpe Center is supporting the Federal Railroad Administration in performing rail passenger equipment crashworthiness research. The overall objective of this research is to develop strategies for improving structural crashworthiness and occupant protection. A field study of passenger train accidents is being conducted to investigate the causal mechanisms of the injuries incurred by train occupants. The investigation of the November 30, 2007 collision in Chicago, IL has provided preliminary data on the structural damage as well as occupant injuries resulting from the impact. This data will be used in simulations to guide the development of crashworthiness strategies.

In Glendale, California on January 26, 2005, impact with an SUV on the track caused a southbound commuter train to derail, impact a standing freight train, buckle laterally outward, and rake the side of a northbound commuter train. Significant deformation resulted in the front of the southbound train and the side of the northbound train. There were a total of eleven fatalities and over one hundred injuries. This incident was investigated as a part of an ongoing field study of occupant injury in passenger train collisions and derailments currently being conducted by the United States (US) Department of Transportation’s (DOT) Rail Accident Forensic Team in support of the Equipment Safety Research Program of the Federal Railroad Administration (FRA). The Forensic Team determined that the primary causal mechanism of injuries and fatalities in the Glendale incident was the loss of occupied volume of the passenger cars brought about by severe structural deformation.

In June 2009, at the request of the Federal Railroad Administration (FRA), the Railroad Safety Advisory Committee established the Engineering Task Force (ETF). The ETF is comprised of government, railroads, suppliers, and labor organizations and their consultants. The ETF was tasked with recommending a process for assessing alternative Tier I passenger rail equipment, i.e., passenger equipment that is operated at speeds up to 125 mph on the general railroad system. The final product of the ETF is a document outlining criteria and procedures for demonstrating crashworthiness performance of passenger rail equipment built to alternative design standards and proposed for operation in the US. The results provide a means of assessing whether an alternative design compares to designs compliant with the FRA’s Tier I crashworthiness requirements. This paper focuses on the criteria and procedures developed for scenario-based requirements. The principle collision scenario describes the minimum train-level crashworthiness performance required in a train-to-train collision of an alternatively designed passenger train with a conventional locomotive-led passenger train. For cab car-led and MU locomotive-led operations, the impact speed is prescribed at 20 mph. For locomotive led operations, the impact speed is prescribed at 25 mph. Criteria for evaluating this scenario include intrusion limits for the passengers and engineer, and occupant protection measures. Other scenario-based requirements discussed in this paper include colliding equipment override, connected equipment override, and truck attachment.

To support the development of a proposed rule [1], a full-scale dynamic test and two full-scale quasi-static tests have been performed on the posts of a state-of-the-art (SOA) end frame. These tests were designed to evaluate the dynamic and quasi-static methods for demonstrating energy absorption of the collision and corner posts. The tests focused on the collision and corner posts individually because of their critical positions in protecting the operator and passengers in a collision where only the superstructure, not the underframe, is loaded. There are many examples of collisions where only the superstructure is loaded. For the dynamic test, a 14,000-lb cart impacted a standing cab car at a speed of 18.7 mph. The cart had a rigid striking surface in the shape of a coil mounted on the leading end that concentrated the impact load on the collision post. During the dynamic test the collision post deformed approximately 7.5 inches, and absorbed approximately 137,000 ft-lbs of energy. The SOA collision post was successful in preserving space for the operators and the passengers. For the quasi-static test of the collision post, the collision post was loaded in the same location and with the same fixture as the dynamic test. The post absorbed approximately 110,000 ft-lb of energy in 10 inches of permanent, longitudinal deformation. For the quasi-static test of the corner post, the post was loaded at the same height as the collision post, with the same fixture. The corner post absorbed 136,000 ft-lb of energy in 10 inches of permanent, longitudinal deformation. The series of tests was designed to compare the dynamic and quasi-static methods for measuring collision energy absorption during structural deformation as a measure of crashworthiness. When properly implemented, either a dynamic or quasi-static test can demonstrate the crashworthiness of an end frame.

Crash Energy Management (CEM) systems protect passengers in the event of a train collision. A CEM system distributes crush throughout designated unoccupied crush zones of a passenger rail consist. This paper examines the influence of manufacturing variations in the CEM system on the crashworthiness of CEM passenger rail equipment. To perform effectively, a CEM system must have certain features. A coupling mechanism allows coupled cars to come together in a controlled fashion and absorb energy. A load transfer mechanism ensures that the car ends mate and maintain contact. A principal energy absorber mechanism is responsible for absorbing the vast majority of crash energy. These components function by providing an increasing force-crush characteristic when they are overloaded. The force-crush behavior can vary due to manufacturing tolerances. For the purposes of this research, the pushback coupler, the deformable anticlimber, and the primary energy absorber were the devices that performed these functions. It was confirmed in this study that the force-crush characteristic of the pushback coupler and the primary energy absorber have the greatest influence on crashworthiness performance. To represent the influence of these parameters, the average force of the pushback coupler and the average force of the primary energy absorber were examined. A cab-led passenger train impacting a standing freight consist was represented as a one-dimensional lumped-mass model. The force-crush characteristic for each coach car end was adjusted to examine the effects of variation in manufacturing. Each car end was modified independently while holding all other car ends constant. The model used in this study was designed to be comparable with a 30 mph, full-scale, train-to-train CEM test. Using crush distribution and secondary impact velocity as measures of crashworthiness, the standard CEM consist performance has a maximum crashworthiness speed limit of 40 mph. Percent total energy absorbed was used as a means of comparison between cars for each consist configuration. When energy absorption levels are decreased at any particular car end, crush tends to be drawn towards this car end. Correspondingly, when available energy levels are increased at a car end, crush is drawn away from this car end. For both cases, the overall distribution of crush has more of an effect locally and less of an effect at other coupled interfaces. This paper shows that moderate variations in crush behavior may occur due to manufacturing tolerances and have little influence on the crashworthiness performance of CEM systems.

To ensure a level of occupant volume protection, passenger railway equipment operating on mainline railroads in the United States must be designed to resist an 800,000-lb compressive load applied statically along the line of draft. An alternative manner of evaluating the strength of the occupied volume is sought, which will ensure the same level of protection for occupants of the equipment as the current test, but will allow for a greater variety of equipment to be evaluated. A finite element (FE) model of the structural components of a railcar has been applied to examine the existing compressive strength test and evaluate selected alternate testing scenarios. Using simplified geometric and material properties, a generic single-level railcar model was constructed that captured the gross behaviors of the railcar without excessive processing time. When loaded, the carbody structure exhibits some single beam-like behaviors. Application of the existing 800 kip compressive load results in a significant bending moment as well as significant compressive forces. The alternative load cases examined show that a larger total compressive force may be distributed across the end structure of the railcar and result in similar stress levels throughout the structural frame as observed from application of the conventional proof load.

In support of the Federal Railroad Administration’s (FRA) Railroad Equipment Safety Program, a full-scale dynamic test of a collision post of a state-of-the-art (SOA) end frame was conducted on April 16, 2008. The purpose of the test was to evaluate the dynamic method for demonstrating energy absorption and graceful deformation of a collision post. The post aims to protect the operators and passengers in the event of a collision where only the superstructure, not the underframe, is loaded. Methods for improving the performance of collision and corner posts were prompted by accidents such as the fatal collision in Portage, Indiana in 1998, where a coil of steel sheet metal penetrated the cab car through the collision post. The improvements made for the SOA end frame structure include more substantial corner and collision posts, robust post connections to the buffer beam and anti-telescoping (AT) beam, and corner and collision posts integrated with a shelf and bulkhead sheet. Full length side sills improved support for the end frame. This test focused on one collision post because of its critical position in protecting the operator and passengers in an impact with an object at a grade-crossing. For the test, a 14,000-lb cart impacted a standing cab car at a speed of 18.7 mph. The cart had a rigid coil shape mounted on the leading end that concentrated the impact load on the collision post. The requirements for protecting the operator’s space state that there will be no more than 10 inches of longitudinal crush and none of the attachments of any of the structural members separate. During the test, the collision post deformed approximately 7.4 inches and absorbed approximately 138,000 ft-lb of energy. The attachment between the post and the AT beam remained intact. The connection between the post and the buffer beam did not completely separate, however the forward flange and both side webs fractured. The post itself did not completely fail. There was material failure in the back and the sides of the post at the impact location. Overall, the end frame was successful in absorbing energy and preserving space for the operators and the passengers.

Research is currently underway to develop strategies for maintaining the structural integrity of railroad tank cars carrying hazardous materials during collisions. This research, sponsored by the Federal Railroad Administration (FRA), has focused on four design functions to accomplish this goal: blunting the impact load, absorbing the collision energy, strengthening the commodity tank, and controlling the load path into the tank. Previous papers have been presented outlining the weight and space restrictions for this new design, as well as the approach being taken in developing the design. The performance goals for the new car have also been outlined. A key goal for the new design is the ability to contain its lading at four times the impact energy of the baseline equipment. Presently, a preliminary design has been developed that will incorporate these four functions together. This new design features a conventional commodity tank with external reinforcements to strengthen the tank. The reinforced tank is situated on a structural foam cradle, within an external carbody. This carbody has been designed utilizing welded steel sandwich panels. The body is designed to take all of the inservice loads, removing the commodity tank from the load path during normal operations. Additionally, the carbody panels will serve as an energy-absorbing mechanism in the event of a collision. Preliminary steps for fabricating and assembling the new tank car design have been outlined. These steps were developed with the intention of paralleling existing tank car fabrication process as much as is practical. Using the commercial finite element analysis (FEA) software ABAQUS/Explicit, the improved design has been analyzed for its response to an impact by a rigid punch. Simulations of two generalized impact scenarios have been made for this rigid punch impacting the improved tank car head as well as the improved tank car shell. Results of these analyses, including the force-displacement curves for both impacts, are presented within this paper. These results show that an improved-design tank car can contain the commodity for a head impact with eight times the energy of the baseline car, and four times the energy for a shell impact.