REDUCING THE HARM IN RAIL CRASHES: ANALYSIS OF INJURY MECHANISMS AND MITIGATION STRATEGIES

摘要

Twenty-three commuter and inter-city passenger train accidents, which occurred over the past twenty years, have been analyzed. The analysis has assessed the potential effectiveness of various injury mitigation strategies. The strategies with the greatest potential to increase passenger safety are interior occupant protection, coupler integrity, end structure integrity, side structure integrity, and glazing system integrity. We recommend that these strategies be researched further. Three types of accidents were analyzed: train-to-train collisions, derailments, and grade-crossing collisions. Train-to-train collisions include the commuter train-freight train collision in Chatsworth, California on September 12, 2008. In Chatsworth a commuter train collided with a freight train at a closing speed of ～80 mph, fatally injuring twenty-five people and injuring more than 100 others. Derailments include the commuter train derailment in Spuyten Duyvil, New York on December 1, 2013, fatally injuring four people and injuring more than fifty others. Grade-crossing accidents include the commuter-SUV collision in Valhalla, New York on February 3,2015, which resulted in six fatally injured people, including the SUV driver, and thirteen severely injured people. Four categories of mitigation strategies were considered: train crashworthiness, wayside structure crashworthiness, fire safety, and emergency preparedness. Within each of these categories are equipment features, which may potentially be modified to further mitigate injuries. The features are simple noun phrases, e.g., "floor strength," implying that the floor strength should be increased. Train crashworthiness includes features such as end strength, floor strength, coupler separation, and numerous others. Wayside structure crashworthiness includes features such as frangible catenary poles and third rail end caps. Fire safety includes train interior and train exterior features for minimizing the potential for fire and for reducing the rate at which fire might spread. Emergency preparedness includes features for emergency egress, access, lighting, signage, and on-board equipment, such as fire extinguishers. Overall, rail passenger travel has a high level of safety, and passenger train accidents are rare events. The numbers are low for expected casualties per passenger-mile and casualties per passenger-trip. A high level of safety, however, does not mean efforts to improve it should cease. But it does mean that crashes are rare events. Rare events in complex systems are notoriously difficult to analyze with confidence. There are too few accidents to provide the data needed for even a moderate degree of mathematical confidence in statistical analysis. Analyses of similar data in medical and scientific fields have been shown to be prone to the biases of the researchers, sometimes in subtle and difficult-to-detect ways. As a means of coping with the sparse data and potential biases, the goal has been to evaluate the accidents transparently and comprehensively. This approach allows a wide audience to understand how injuries and fatalities occur in passenger train accidents and, most importantly, allows us to prioritize mitigation strategies for research.