Development of Crash Energy Management Designs for Existing Passenger Rail Vehicles

Abstract

As part of the passenger equipment crashworthiness research, sponsored by the Federal Railroad Administration and supported by the Volpe Center, passenger coach and cab cars have been tested in inline collision conditions. The purpose of these tests was to establish baseline levels of crashworthiness performance for the conventional equipment and demonstrate the minimum achievable levels of enhancement using performance based alternatives.The alternative strategy pursued is the application of the crash energy management design philosophy. The goal is to provide a survivable volume where no intrusion occurs so that passengers can safely ride out the collision or derailment. In addition, lateral buckling and override modes of deformation are prevented from occurring. This behavior is contrasted with that observed from both full scale tests recently conducted and historical accidents where both lateral buckling and/or override occurs for conventionally designed equipment.A prototype crash energy management coach car design has been developed and successfully tested in two full-scale tests. The design showed significant improvements over the conventional equipment similarly tested. The prototype design had to meet several key requirements including: it had to fit within the same operational volume of a conventional car, it had to be retrofitted onto a previously used car, and it had to be able to absorb a prescribed amount of energy within a maximum allowable crush distance. To achieve the last requirement, the shape of the force crush characteristic had to have tiered force plateaus over prescribed crush distances to allow for crush to be passed back from one crush zone to another. The distribution of crush along the consist length allows for significantly higher controlled energy absorption which results in higher safe closing speeds.

Evaluation of Occupant Volume Strength in Conventional Passenger Railroad Equipment

“…At the same time, the United States Post Office had a number of Railway Post Office (RPO) cars in operation across the country [5]. These cars acted as mobile post offices, where clerks processed mail while the train was en route to its destination.…”

Strategy for Alternative Occupant Volume Testing

“…The CEM system is described in detail in Martinez, et. al [5]. A CEM crush zone of the type previously installed on the test car is shown in Figure 5.…”

Preparations for a train-to-train impact test of crash-energy management passenger rail equipment

“…Shear bolts connect the sliding sill to the fixed sill and shear rivets connect the inner tube to the outer tube of the roof absorbers and act as structural fuses; the trigger load is approximately 1.2 million pounds. The details of this design are described further in the reference [11]. Figure 6 shows the two Pioneer coach cars shortly before the two-car impact test.…”

“…Therefore, the crush-zone design in the cab car must fulfill more design requirements than the coach car. To achieve these goals, the cab car design relies on concepts developed in the coach car crush zone design [11] and a study of effective anti-climbers [12].…”