RTDF2008-74020 A DYNAMIC TEST OF A COLLISION POST OF A STATE-OF-THE-ART END FRAME DESIGN

Abstract

ABSTRACT 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. INTRODUCTION As a result of consideration of both a notice of proposed rulemaking (NPRM) for improved cab car multiple unit (MU) locomotive equipment and the accepted industry standard, a series of tests were planned to demonstrate examples of conducting such tests to shows equivalence between testing protocols. Three test scenarios are taken from the FRA's proposed rule [1]. This paper covers the dynamic test of a collision post. There are two quasi-static tests also being planned. The quasi-statics tests are on the collision post and the corner post. Both the proposed rule and the industry standard improve crashworthiness performance due to increased static load requirements, as well as minimum energy absorption and maximum allowable intrusion into the cab. By encouraging improved energy absorption capabilities for the end frames, the rule aims to improve survivability for operators and passengers at higher collision speeds