The Educational Railroading Conference Leader Since 1994


2021 Rail Transit Session


Enhancing Instrumented Wheelset Data To Better Predict Derailment Risk

Russell Walker

Russell Walker
Transportation Technology Center Inc.

Qualification of new passenger and transit rolling stock can involve testing with Instrumented Wheelsets (IWS) to measure the forces between the wheels and rails. This testing is often done in a series of runs incrementally increasing in speed over a specified test section. The instrumentation, including IWS, measures vehicle performance for comparison to vehicle/track interaction safety limits. Recent research by TTCI has found that the current Lateral/Vertical load (L/V) ratio-based criteria does not always assess the risk of derailment accurately because the friction between the wheel and rail is not known precisely. This led to a recent flange climb derailment during qualification testing of a prototype rail vehicle in a sharp curve. TTCI’s IWS processor was enhanced to use the wheel profile to determine Wheel/Rail (W/R) vertical contact position and contact angle to better predict risk of derailment. The improved IWS processor is now being utilized to assess derailment risk during qualification testing of new rolling stock for both transit and freight.