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.

车轮爬升脱轨经常发生在道岔中。这通常是因为道岔区域的轨道走线很差，并且道岔轨道的横截面不均匀。以前的大多数研究都集中在直线或曲线上的脱轨。因此，了解道岔中的脱轨机制并揭示轮对运动条件对动态脱轨行为的影响对于制定所需的动态脱轨标准至关重要。本文建立并验证了用于脱轨仿真的半车多体动力学模型。然后，进一步分析了三种不同行驶工况在不同轮对运动条件下的效果。结果表明，与直线和曲线相比，开关轨道沿纵向的可变截面和较小的接触角是车轮爬升脱轨的根本原因。轮子在轨顶宽度为 5 至 20 mm 的区域开始爬上道岔轨道。如果忽略道岔的影响，导轨中的脱轨风险就会显着降低。本文有助于减轻铁路道岔脱轨以及制定安全评估标准。