Remote detection of derailment of a wagon of a freight train: theory and experiment

Abstract

The paper discusses the possibility to detect derailment of a train's wagon by measuring vibrations of the rails under the locomotive. Both theoretical and experimental studies have been carried out, followed by a comparison of their results. For the theoretical modelling of the railway track, a Timoshenko beam resting on discrete, equidistantly spaced supports is used. The steady-state response of the beam to a load that either uniformly moves along the beam or uniformly `jumps' from support to next support is investigated at a point, which remains at a fixed distance from the moving load. The load that moves along the beam is used to model the `normal motion' of a train's wheelset, whereas the `jumping' load is employed to model the action of a derailed wheelset. It is shown that the effect of the derailed wheel-set consists of an amplification of the rail's response in the frequency band that surrounds the natural frequency of the sleeper's vibrations. This theoretical prediction is confirmed experimentally. A method of processing the measured data is proposed that allows for stable detection of the derailment. A maximum distance between the locomotive and the derailed wagon is estimated, at which the detection is possible.