Investigation of Hybrid Fuel Cell (HFC) Technology Applications on the Future Passenger Railroad Transportation

Due to the consideration of fragile security, and longer check-in times and inconveniences due to increased air travel security examination since September 11th 2001, more and more people have turn to ground transportation. Unfortunately, the inefficient, environment-unfriendly and unsafe passenger cars and buses are the only choices available for middle distance trips. Development of high efficiency, clean and high speed railroad passenger transportation system has become more necessary to overcome this weak link. In this paper, the applicability of hybrid drive train technologies for middle-distance passenger train locomotives will be investigated. A systematic design of the diesel based hybrid locomotive helps to increase efficiency, improve fuel economy, reduce emissions and also reduce mass production costs. Furthermore, professional management and maintenance of railroad train locomotives make such new technologies more practical than for road vehicles. The success of such transportation system will have a great positive impact on our social activities, quality of life, energy supply, environment and economy. A diesel based hybrid electric locomotive (HEL) with batteries or an ultracapacitor is an option to reduce fuel consumption and emissions and provide better performance and fuel economy. The reduced fuel consumption helps reduce the amount of pollutants released. Engineering estimation indicate that emissions will be reduced by 70% and fuel efficiency will be increased by at least 30% in hybrid locomotives.

Collision Safety Comparison of Conventional and Crash Energy Management Passenger Rail Car Designs

In conjunction with full-scale equipment tests, collision dynamics models of passenger rail cars have been developed to investigate the benefits provided by incorporating energy-absorbing crush zones at the ends of the cars. In a collision, the majority of the structural damage is generally focused at the point of impact for cars of conventional design. In contrast, cars with crush zones, or crash energy management (CEM), can better preserve occupied areas by distributing crush to the ends of cars. Impact tests of conventional equipment have already been conducted, which consisted of a single car and two coupled cars colliding with a rigid wall. Corresponding tests are planned using CEM equipment. This paper presents preliminary predictions of the one- and two-car CEM tests, and compares them to the results of the respective conventional equipment tests. The comparison will focus on loss of occupant volume, secondary impact velocity (SIV), and lateral buckling, as measures of occupant protection. The modeling results indicate that the occupant volume can be preserved in both the one-car and two-car tests of the CEM equipment, while 2 1/2 and 3 feet of occupant volume were crushed in the respective tests of conventional equipment. In the two-car model, the CEM design is able to distribute the crush between both cars, whereas the conventional design incurs nearly all the crush at the point of impact. The CEM design can absorb more energy without crushing the occupied area because it requires a higher average force per foot of crush at the vehicle ends. The trade-off associated with this higher crush force is generally a higher SIV for occupants in the CEM cars. Secondary impact velocity refers to the velocity at which an occupant strikes some part of the interior, in this analysis the back of the seat ahead of the occupant. The greatest SIV penalty is in the impacting car. The difference between the SIV for cars in a conventional and a CEM consist decreases in each trailing car. That is, the SIV generally decreases in each trailing car of a CEM consist, while the SIV remains approximately the same in each trailing car of a conventional consist.

Rail Car Impact Tests With Steel Coil: Collision Dynamics

Two full-scale oblique grade-crossing impact tests were conducted in June 2002 to compare the crashworthiness performance of alternative corner post designs on rail passenger cab cars. On June 4, 2002 a cab car fitted with an end structure built to pre-1999 requirements impacted a steel coil at approximately 14 mph. Following, on June 7, 2002 a cab car fitted with an end structure built to current requirements underwent the same test. Each car was equipped with strain gauges, string potentiometers and accelerometers to measure the deformation of specific structural elements, and the longitudinal, lateral and vertical displacements of the car body. The gross motions of the cars and steel coil, the force/crush behavior of the end structures, and the deformation of major elements in the end structures were measured during the tests. During the first test, the car fitted with the 1990’s design end structure acquired more than 20 inches of longitudinal deformation causing failure at the corner post and resulting in the loss of operator survival space. During the second test, the corner post on the car fitted with the State-of-the-Art design deformed longitudinally by about 8 inches, causing no failure and consequently preserving the survivable operator volume. In both cases, the steel coil was thrown to the side of the train after impacting the end structure. Prior to the tests, the crush behaviors of the cars and their dynamic responses were simulated with car crush and collision dynamics models. The car crush model was used to determine the force/crush characteristics of the corner posts, as well as their modes of deformation. The collision dynamics model was used to predict the extent of crush of the corner posts as functions of impact velocity, as well as the three-dimensional accelerations, velocities, and displacements of the cars and coil. Both models were used in determining the instrumentation and its locations. This paper describes the collision dynamics model and compares predictions for the gross motions of the cars and coils made with this model with measurements from the tests. A companion paper describes the car crush model and compares predictions made of car crush with measurements from the test. The collision dynamics was analyzed using a lumped-parameter model, with non-linear stiffness characteristics. The suspension of the car is included in the model in sufficient detail to predict derailment. The model takes the force/crush characteristic developed in the car crush analysis as input, and includes the lateral force that develops as the corner post is loaded longitudinally. The results from the full-scale grade-crossing impact tests largely agree with and confirm the preliminary results of the three-dimensional lumped parameter computer model of the collision dynamics. The predictions of the model for the three-dimensional accelerations, velocities, and displacements of the car and the coil are in very close agreement with the measurements made in the tests of both cars, up to the time of failure of the corner post. The cars remained on the track in both tests, as predicted with the model.

Design, Fabrication, Testing, and Fuzzy Modeling of a Large Magnetorheological Damper for Vibration Control in a Railcar

This paper presents the procedure used for design, fabrication, testing, and numerical modeling of a magnetorheological (MR) damper that is to be applied for vibration control in a 70-ton railcar. MR dampers are semiactive vibration control devices whose damping characteristics can be modified in real time by varying an applied current. Design parameters for the MR damper are estimated from those exhibited by a linear viscous damper that exerts the necessary force required to limit vertical vibrations of the rail truck within acceptable limits. An MR damper is fabricated by modifying the piston of a standard hydraulic damper to function as a solenoid. The assembled MR damper is tested in a uniaxial testing machine by subjecting it to sinusoidal and random displacements while simultaneously varying the current flowing in the solenoid. A variable magnetic field is applied to the MR fluid that fills the damper cavity and the resisting force exerted by the damper is recorded. Data collected in the laboratory are used to train a fuzzy model of the MR damper that characterizes its behavior. Results indicate that a fuzzy model of the MR damper can predict its behavior with a sufficient degree of accuracy while requiring minimal computational time.

The Influence of Suspension System Design on Vertical Loads Imposed on the Track

The relative significance of vehicle dynamics on the dynamic component of wheel-rail interface vertical forces caused by relatively short wavelength track perturbations is estimated, based on a simple dynamic model, for a range of suspension design types. The results indicate the relative importance of suspension design on track damage. This study is analytical. However, it provides a basis for testing to ensure that the influence of suspension design on track-induced vertical loads is better documented and understood.

On the Dynamics of the Three-Piece-Freight Truck

This paper is based on part of Fujie Xia’s PhD-thesis [8] on the modelling and dynamics of the Three-Piece-Freight Truck.

Rail-Car Impact Tests With Steel Coil: Car Crush

Two grade-crossing impact tests were conducted in June 2002 at the Federal Railroad Administration’s (FRA’s) Transportation Technology Center in Pueblo, Colorado as part of the FRA’s research into passenger equipment crashworthiness. In both of these tests a cab car moving at approximately 14 mph impacted a standing coil of steel supported by a frangible table. The coil was positioned such that the left-side corner post of the cab car sustained the brunt of the impact. The cars were instrumented to measure the accelerations of the carbody, the displacements of the suspensions, the displacements of the corner posts, and the strains in selected structural members. The coil was instrumented to measure its three-dimensional acceleration, including yaw, pitch, and roll. On-board and wayside high-speed film and video cameras were used to record the impact. On June 4, 2002 a cab car compliant with general industry practice circa 1999 was tested and on June 7, 2002 a cab car compliant with current FRA regulations and American Public Transportation Association (APTA) Standards and Recommended Practices for Rail Passenger Equipment was tested. The tests themselves were conducted in response to a recommendation from the APTA Passenger Rail Equipment Safety Standards (PRESS) Committee to measure the crashworthiness performance of alternative cab car end structures. During the test of the 1990’s design, the corner post failed, eliminating the survival space for the operator. During the test of the state-of-the-art design cab car, the corner post remained attached and deformed less than 9 inches, preserving space for the operator. Prior to the test, crush analyses were conducted to determine the force/crush characteristics of the two end structure designs, as well as their modes of deformation. Collision dynamics analyses were also conducted to determine the extent of crush and the gross motion of the car and coil. This paper describes the analysis of the crush behaviors of the two different end structure designs. A companion paper describes the results of the collision dynamics analyses. The crush of the cars was analyzed using detailed finite-element models. The impact end of each car was modeled, including approximately 1/4 of the length of the car. The back end of the cab car model was fixed, and its end structure was impacted by an initially moving cylinder with the same mass and dimensions as the steel coil used in the tests. Prior to the tests, runs were made with the models with and without material failure. This approach allowed calculation of an upper bound and a lower bound on the force/crush characteristics. The pre-test predictions of the analysis of the state-of-the art car including material failure very closely match the results of the test for the force/crush characteristic, strains at the measured locations, the geometry of the deformed structure, and the locations and extent of material failure. The pre-test predictions of the analysis of the 1990’s design also closely match the test measurements, however, the extent of material failure predicted was slightly less than observed in the test; failure of the corner post was predicted to occur at a speed of a 1.6 mph (approximately 10%) greater than the test speed. A more sophisticated implementation of the material failure modeling helped bring the model results into very close agreement with the test measurements.

The Development of a Rail Passenger Coach Car Crush Zone

This paper presents information on the design of a rail vehicle crush zone for better occupant protection. The overall design requirements and characteristics are described and the configuration for the various structural subsystems is presented. The paper also includes information on full-scale component tests carried out to support the development of the design, particularly for the primary energy absorbers. Comparisons between test and finite element analysis are presented and there is a discussion of how the test results have affected the design.

Wheel Flat and Out-of-Round Formation and Growth

Wheel flats and out-of rounds (OORs) are defects that can cause high impacts that impart damage to track and equipment. This paper presents an analysis of data gathered from wheel impact load detectors on the Union Pacific Railroad and data gathered from the Transportation Technology Center, Inc. (TTCI) Wheel Defect research Consortium.