Study on the Safety Boundary for High Speed Trains in Severe Environments

Abstract

The paper briefly introduces the development plan of high speed railways in China in the near future. A few serious derailment accidents in the world are listed and the corresponding causes are briefly described. In this paper these causes are defined as the extremely severe environments in which the trains operate. The paper reviews the important published papers regarding the discussions on the mechanisms and the modelling of trains running in such severe environments. The traditional derailment criteria are briefly discussed. A traditional geometry criterion for estimating train safety operation is further improved and discussed. The strategy of the study on the safety operation boundaries of the high speed trains running in severe environments is put forward. In the strategy, the safety operation boundaries are strictly defined. They are found through the numerical simulation by using the theoretical models for vehicle/track and the derailment criteria. The paper introduces the theoretical models for the high speed vehicle and the two kinds of the high speed tracks. The two kinds of the tracks are, respectively, the ballasted track and the slab bed track. Only the model for the high speed vehicle coupled with the ballasted track is employed in the calculating the safety operational boundaries for the high speed train passing over the bulked tangent track as a numerical example in order to fully understand the present strategy. The results include the dynamical behaviours of the wheelsets, the transient derailments and the safety operation boundaries.