Influence of the motion conditions of wheelsets on dynamic derailment behaviour of a bogie in railway turnouts

Wheel climb derailment frequently occurs in turnouts. This is usually because track alignments in the turnout area are very poor and the cross-sections of switch rail are not uniform. Most previous studies focused on derailments in straight or curved lines. For this reason, understanding the derailment mechanism in turnouts and revealing the influence of the wheelset motion conditions on dynamic derailment behaviour are fundamental for the development of the required dynamic derailment criteria. For this paper, a half-vehicle multi-body dynamic model for derailment simulation was established and validated. Then, the effect of three different running cases with different wheelset motion conditions was further analysed. The results show that the variable cross-sections of switch rail along the longitudinal direction with a small contact angle are the root cause of the wheel climb derailment when compared with straight and curved lines. The wheels start climbing the switch rail at regions of rail top width from 5 to 20 mm. If the effect of the switch rail is ignored, the derailment risk in the guide curve is significantly reduced. This paper can contribute to the mitigation of derailment in railway turnouts as well as to the development of safety assessment criteria.

Automated summary

The study highlights that wheel climb derailment often occurs in the turnout area due to poor track alignment and uneven switch rail cross-sections. Different wheelset motion conditions can impact derailment behavior, and ignoring the effect of the switch rail can significantly reduce derailment risk.