The influence of track geometry on frelght wagon derailment on straight track: computer simulation and wayside test study in China

摘要

Systematic computer simulation study and wayside test have been carried out recently to investigate how track geometry contributes to several severe unloaded freight wagon derailment accidents taken place recently in China on straight track. NUCARS, developed by AAR, is used to simulate vehicle/track dynamic response and derailment safety when empty freight wagon is running on traight track with various geometry irregularities, or straight track setting a height difference between left and right rail, or track with gauge has been narrowed down. Based on these simulation reuslts, wayside test has been conducted in a range of 4.6 meters and wheel/rail contact status is recorded by photographic method. The computer simulation and test results show that even small geometry irregularities may play a great role in increasing risk of derailment if severe hunting movement has taken place; furthermore, irregularities with wavelength in an unfavorable range may cause lager derailment quotient and rate of wheel load reduction and hence increase the risk of derailment. Some measures such as smearing rails with oil and elevating one side of rails of the straight track are tested to be helpful to restrain hunting movement of freight wagon to lower the possibility of derailment.