Preliminary Study On The Derailment Effect By Rail Motions

The basic requirement for the safety of railway transportation system is that derailment during the running of train should never be permitted. The mechanism of derailment has been investigated by almost all railway administrations and scientists for many years. Much progress has been made with theoretical and experimental methods. However, due to the complexity of derailment and the difficulty of research, derailment accidents still often happen. Especially in china, derailment accident accounts for about 70 percent of traffic accidents on railway transportation, which has a significant influence on the economy and society benefit of railway transportation of China. In the past studies, the effect of the motions of wheelset and rail on the contact geometry, creepage, creep force and derailment in wheel/rail rolling contact is not yet taken into consideration. The current study is summarized as follows:(1) Based on the elastic rail model and the relationship of wheel/rail spatially contact geometry, the traditional least-distance-search algorithm is improved by fitting the treads of wheelset and rail into a cubic interpolation function. A amendatory algorithm for wheel/rail spatially contact geometry is proposed, which can take the rail roll-over, rail lateral displacement and rail vertical displacement into account. According to the developed algorithm, the effect of rail roll-over, rail lateral displacement and rail vertical displacement on wheel with cone-tread and worn-tread and rail contact geometry is analyzed.(2) A wheel/rail rolling contact creepage which can consider the effect of rail roll-over, rail lateral displacement and rail vertical displacement is obtained. Kalker's linear theory and Shen-Hedrick-Elkins non-linear theory are employed to determine creep forces. The influence of rail roll-over, rail lateral displacement and rail vertical displacement on creep force and creepage of wheel/rail is analyzed.