Development and Fabrication of State-of-the-Art End Structures for Budd M1 Cars

The Volpe Center and the Federal Railroad Administration are engaged in active research aimed at improving rail vehicle crashworthiness. One component of this research is focused on improving the performance of passenger train cab cars during collisions with heavy objects at grade crossings. New standards have been approved by the American Public Transportation Association that increase the strength requirements for cab car end structures and impose further requirements on their ability to absorb energy during a collision. The FRA has issued a notice of proposed rulemaking (NPRM) to include these new standards in 49CFR238.211. These standards include requirements for demonstration of energy absorption through either quasi-static or dynamic tests. The intent of each test method is to demonstrate a minimum level of energy absorption—120,000 ft-lbs for a corner post load and 135,000 ft-lbs for a collision post load—while limiting occupied volume intrusion to less than 10 inches. To aid in the development of these new standards, the FRA and Volpe Center are conducting a set of three tests: quasi-static loading of both the collision and corner posts, and dynamic loading of the collision post only. (A dynamic test of the corner post was conducted as part of an earlier program). These tests were developed to illustrate testing methodologies and to demonstrate the feasibility of the new energy absorption and large deformation requirements. In+ each test, the post is loaded 30 inches above the underframe by a proxy object that is 36-inches wide, with a 48-inch diameter cylindrical face. In support of this testing program, the research reported here focused on the design and fabrication of end frames suitable for retrofitting onto the cab end of a Budd M1 cab car. The design of an end frame for retrofit onto the cab end of a Budd Pioneer cab car was modified to account for differences between the two car designs. In addition, reinforcements to the M1 car body and connections from the end frame to the car body were designed and fabricated. An FEA model of the end frame retrofit onto the M1 cab car was developed based upon the detailed design. A series of linear and nonlinear static, quasi-static, and dynamic FEAs were performed to evaluate the performance of the design. Preliminary analyses revealed the need for a few minor modifications to the connections in order to meet design requirements; these were incorporated into the final design for manufacture. Components for the end frame, connections between the end frame and the car body, and reinforcements to the car body were fabricated based on detailed design drawings and then assembled and connected to the reinforced M1 Car, from which the original end frame had been cut off. A successful dynamic test was completed in April, 2008; quasi-static tests are scheduled for summer 2008. The results of FEA model predictions are compared with the results of the dynamic test.