Robert Rancatore

A Crush Zone Design for an Existing Passenger Rail Cab Car

A Crash Energy Management (CEM) cab car crush zone design has been developed for retrofit onto an existing Budd M1 cab car. This design is to be used in the upcoming full-scale train-to-train test of a CEM consist impacting a standing freight consist of comparable weight. The cab car crush zone design is based upon the coach car crush zone design that has been previously developed and tested. The integrated system was developed after existing national and international CEM systems were reviewed. A detailed set of design requirements was then drafted, and preliminary designs of sub-assemblies were developed. The preliminary designs were analyzed using detailed large deformation finite element software. Performance of the cab car crush zone under ideal and non-ideal loading conditions was analyzed prior to development of the final design. The key components of the design include: a long stroke push-back coupler capable of accommodating the colliding locomotive coupler, a deformable anti-climber to manage the colliding interface interaction, an integrated end frame on which the deformable anti-climber is attached, a set of primary energy absorbers designed to crush in a controlled manner while absorbing the majority of the collision energy, and a survivable space for the operator which pushes back into an electrical closet. The cab car crush zone is designed to control both lateral and vertical vehicle motions that can promote lateral buckling of the train and override of the impacting equipment. The design is capable of managing the colliding interface interaction with a freight locomotive and passing crush back to successive crush zones. Detailed fabrication drawings have been developed and submitted to a fabrication shop. In addition, existing Budd M1 cars are being prepared to receive the retrofit components.Copyright

Development of a passenger rail vehicle crush zone

The use of crush zones in passenger rail vehicles is rapidly growing in the United States and throughout the world. Such crush zones are an important part of the crash energy management philosophy of train occupant protection. The objective of this study was to determine the advantages, disadvantages and issues related to incorporating crush zones at the ends of coach cars for protection in collisions between two trains. The general specifications for the crush zone were selected after consideration of the energy and forces that can be accommodated in such structures. Various designs were considered to meet these requirements and one of these was selected for more detailed development and evaluation. The effort included design layout and nonlinear dynamic finite element analysis to determine crush response.

Analysis of colliding vehicle interactions for the passenger rail train-to-train impact test

A full-scale train-to-train impact test was performed in which a cab car-led passenger train traveling at 30 mph collided with a standing locomotive-led train. During the test, the lead cab car overrode the cab of the standing locomotive, sustaining approximately 20 feet of crush, while the cab of the locomotive remained essentially intact. In this study, a finite element-based analysis of the collision was performed. The first 0.5 seconds of the collision was simulated. Results of the analysis were compared with accelerometer and video test data. Specific comparisons are made between test data and model predictions for: motions of the cab car and the standing locomotive; longitudinal forces arising between the cab car and the standing locomotive and between the respective lead and trailing vehicles; and the mode of deformation of the cab car and the locomotive. The results of the study indicate that the model captures pertinent features of the first 0.3 seconds of the collision, particularly with respect to longitudinal vehicle motions and collision forces. After 0.3 seconds, agreement between model predictions and test data becomes progressively worse. This is attributable to the models inability to capture the massive fracture that occurs at the front of the cab car.

Fullscale two-car impact test: a comparison of measured and model results

The Volpe National Transportation Systems Center is conducting research into the crashworthiness of rail vehicles in support of the Federal Railroad Administrations Office of Research and Development. The approach taken has focused on the review of accidents, development of analytical tools and performing full-scale testing. A series of inline full-scale impact tests have been performed using conventional passenger cars. Recent full-scale testing included two instrumented coupled conventional passenger cars impacting a fixed barrier at 26 mph. The cars were instrumented with accelerometers, strain gages and string potentiometers. From these measurements, car translations, rotations, relative displacements and coupler forces were calculated. A rigid body dynamics model of the two-car configuration was developed and used to design the test. In order to improve the collision dynamics models of passenger cars, the results from this test are being used to refine that model. This paper describes the two-car impact test, the reduction of data collected during the test and the refined collision dynamics model. Post-test refinements allow the model to more accurately simulate the vertical and lateral motions of the cars, including the timing of the lateral buckling of the cars. The post-test model also more accurately simulates the climbing of the impact car as it crushes. Comparisons between the refined model results with the measured data are presented for the motion of the center of gravity of the cars, coupled car interactions and forces, and lateral buckling.