Abstract A comprehensive investigation of the Sydney Trains railway network has been carried out to control and minimize rail degradation, especially squat defects. Squat occurrence was analysed with respect to the parameters of traffic operation and track geometry. Detailed metallurgical examination of the ex-service rails revealed a possible connection between brittle White Etching Layers (WELs) and the occurrence of squats in the running band of the rail. Initiation of squats was found to be associated with the progression of surface cracks in the WELs. Furthermore, two distinguishable types of WELs were found, based on different track operational conditions. These are described as Thermally Produced WEL (TP-WEL) which was found in heavy braking regions, and Severe Deformation WEL (SD-WEL) which was found in track regions under steady traffic speeds. In addition to the explanations based on thermal phase transformation and severe plastic deformation, the arcing phenomenon associated with electrical leakage at the wheel/rail interface was considered an alternative formation mechanism of WELs observed on rails. A revised rail grinding strategy was proposed by considering the formation of WELs and addressing it through more regular, relatively shallow grinding to effectively control squat defects.

中文翻译：

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某铁路网矮陷缺陷的认识与处理

摘要 对悉尼火车铁路网络进行了全面调查，以控制和最大限度地减少铁路退化，尤其是低矮缺陷。根据交通运行和轨道几何参数分析了下蹲发生。对退役钢轨进行详细的冶金检查表明，脆性白色蚀刻层 (WEL) 与钢轨运行带中发生的下陷之间可能存在联系。发现深蹲的开始与 WEL 表面裂纹的进展有关。此外，根据不同的轨道运行条件，发现了两种不同类型的 WEL。这些被描述为热产生的 WEL (TP-WEL)，它在重型制动区域被发现，和严重变形 WEL (SD-WEL)，这是在稳定交通速度下的轨道区域中发现的。除了基于热相变和严重塑性变形的解释外，与轮轨界面漏电相关的电弧现象被认为是在轨道上观察到的 WEL 的替代形成机制。通过考虑WEL的形成并通过更规律、相对较浅的磨削来解决该问题，提出了一种修正的钢轨磨削策略，以有效地控制下陷缺陷。