Abstract On the sloping section of a train service line located in mountainous areas, idling and skidding of the wheels caused by leaves that fall on the railhead in autumn often occurs, and this hinders the scheduled operation of the train. Although countermeasures such as spraying sand or ceramic particles onto the contact zone of wheel/rail are adopted, the effect is insufficient in late autumn. For clarifying the mechanism of the decrease in the adhesion between the wheel and the rail based on fallen leaves and acquiring information useful for practical implementation of countermeasures, the authors conducted a vehicle running test with driving and braking operations on a test line to investigate the occurrence of wheel slipping/sliding under various railhead states such as dry/wet leaves and dry/wet black accretion films, as well as the adhesion coefficient between the wheel and the rail when dry/wet black accretion films exist on the railhead. The results clarified that the wheel slipping/sliding was likely to occur under wet conditions, in particular frequently occur while wet black accretion films exist on the railhead, and then a low adhesion coefficient was recognized under the same conditions. Regarding the black accretion film formation process, the authors reproduced by a rail cooling device which can simulate atmospheric temperature in mountain area, and clarified that the tannin contained in the crushed fallen leaves has a reaction with steel comment of rail under wet (condensation, frost, light rain etc.) conditions and then black tannin iron was generated and adhere to the railhead. The countermeasure of wheel slip/slide should be focused on how to prevent the formation of the black accretion films or remove the black accretion films in the future work.

中文翻译：

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落叶引起的车轮打滑/滑动和低附着力

摘要 位于山区的列车服务线斜坡段，经常发生秋季落叶落到轨头造成车轮空转和打滑现象，阻碍了列车的按期运行。虽然采取了在轮轨接触区喷砂或陶瓷颗粒等对策，但在深秋时效果不明显。为了弄清基于落叶的轮轨附着力降低的机理，并获取对实际实施对策有用的信息，作者在测试线上进行了带有驱动和制动操作的车辆运行测试，以调查发生情况。车轮在各种轨头状态下打滑/滑动，例如干/湿树叶和干/湿黑色增生膜，以及当轨头存在干/湿黑色沉积膜时车轮与轨道之间的附着系数。结果表明，在潮湿条件下，车轮打滑很可能发生，特别是在轨头上存在潮湿的黑色沉积膜时经常发生，然后在相同条件下识别出低附着系数。关于黑色堆积膜的形成过程，作者通过一个模拟山区大气温度的轨道冷却装置进行了再现，并澄清了粉碎的落叶中所含的单宁与轨道在潮湿（冷凝、霜冻）下的钢评有反应。 、小雨等）条件，然后黑色单宁铁生成并粘附在轨头上。