Session: 15-06-01: Reliability and Safety in Transportation Systems I

Paper Number: 165286

Locomotive Override: Recent Incidents Survey and Override Analysis Study 

Research to develop new technologies for increasing the safety of passengers and crew in rail equipment is being directed by the Federal Railroad Administration’s (FRA’s) Office of Research, Data, and Innovation (RD&I). Two crash energy management (CEM) components that can be integrated into the end structure of a locomotive were developed: a push-back coupler (PBC) and a deformable anti-climber (DAC). These components are designed to work in unison to inhibit override in the event of a collision. The results of vehicle-to-vehicle override, where the strong underframe of one vehicle, typically a locomotive, impacts the weaker superstructure of another vehicle, can be devastating and compromise the occupied space. These CEM components were specifically designed to mitigate the effects of a collision and to prevent override of one of the lead vehicles onto the other. They were designed to improve the crashworthiness of CEM-equipped locomotives in a wide range of potential collisions, including collisions with conventional locomotives, conventional cab cars, and freight equipment. In a follow-on CEM locomotive override impact test program, the two CEM components were integrated into the end structure of a conventional locomotive. Through a series of full-scale vehicle coupling and collision tests, the test program successfully demonstrated that these components work together to mitigate the effects of a collision and prevent override.

To inform the CEM locomotive override impact test program, research was conducted to quantify and evaluate recent locomotive override incidents. A survey of incidents where a locomotive either overrode or was overridden by colliding equipment was conducted. Details from each incident are provided, including what occurred in the collision, the speed at impact, the number of injuries and fatalities, whether the incident was preventable with Positive Train Control (PTC), and how the equipment behaved in the incident. Patterns and trends in how the equipment behaved in the incidents are identified and evaluated. The incident survey includes both freight and passenger equipment and endeavors to identify the modes of deformation that lead to override.

The knowledge gained from the CEM locomotive override impact test program and the evaluation of the locomotive override incidents were used to conduct a locomotive override analysis study. The override analysis study objectives were to demonstrate whether a CEM-equipped locomotive reduces the propensity for override in a head-on collision between two consists relative to an identical collision involving a conventional locomotive, and to determine the extent to which various factors affect the propensity for override. Multiple finite element models were generated and exercised to incite and identify modes of deformation that lead to override. This paper provides a summary of the locomotive override incidents, and details the override analysis study approach, model development, and analysis results and evaluation.

Presenting Author: Patricia Llana USDOT Volpe Center

Presenting Author Biography: Patricia Llana is a Senior Mechanical Engineer at the Volpe Center, part of the U.S. Department of Transportation. She received her Bachelor of Engineering degree from The Cooper Union, and her Master of Science degree from MIT, both in Mechanical Engineering. Patricia has over 27 years of experience conducting research to develop strategies for improving the structural crashworthiness and occupant protection of rail equipment.

Authors:

Patricia Llana USDOT Volpe Center
Richard Stringfellow CAMX Power LLC