Vehicle Dynamics Models for Derailment Incident Investigation
When investigating a train derailment, vehicle/track interaction (VTI) using vehicle dynamics simulations of the key vehicles in the derailed train can help identify specific derailment causes. From September 2018 to March 2021, the Federal Railroad Administration (FRA) contracted Sharma & Associates, Inc. to develop a set of railway freight car models for the most prevalent car types in service using VAMPIRE®, a vehicle dynamics simulation software used in the railroad industry. The car types modeled in this research include hopper, covered hopper, lain box, equipped box (including refrigerated), tank, flat, double-stack, gondola and bi-level and tri-level Autorack. The team also created a library of wheel and rail profiles as well as track layout models for a range of curvatures. The results of the vehicle dynamics analyses of several freight car types illustrate the effectiveness of the modeling techniques in predicting key parameters of VTI. The team found that the vehicle dynamics models made from the library of cars, wheel, and rail profile combinations can be used in future derailment investigations when VTI is considered a possible cause. Based on measured track geometry data collected during an incident investigation, researchers can include track defects data to simulate a specific derailment.