The statistical analysis performed on the defectiveness of rails in the Kiev subway railway shows that the main cause of the occurrence of most defects is the contact fatigue of the rail material. The paper presents modern concepts of crack growth in the railhead. It has been found that one of the most promising directions of studying the stress-strain state of rails and the crack growth process is a numerical simulation, which results on the contact interaction between rails and subway rolling stock wheels are presented. During the simulation, the problem was solved in an elastic formulation. We considered R50, R65, and UIC60 rail profiles, standard railway wheels, and wheels whose tire profile was developed by the Minetek closed joint-stock company. The conditions for the rail–wheel interaction corresponded to train movement on the straight section of the track without slipping. The effect of the wheel tire profile on the contact stress level in rails of different types has been assessed. Comparison of the maximum equivalent stress levels for a different combination of rail and wheel types shows that the best combination (in terms of reducing the contact stress level) for the straight sections of the subway track is an R50 rail with a gradient of 1 in 20 and 1 in 10 taper wheel, whose profile corresponds to GOST 9036-88. When wheels with the profile developed by the Minetek company are used, the maximum equivalent stress level in the contact zone is over 1000 MPa for all rail types. It is higher than the yield strength of rail steel, which will accelerate wear and give rise to low-cycle fatigue cracks with subsequent formation of contact fatigue defects.

中文翻译：

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轨道车轮轮胎轮廓对地铁轨道接触应力水平的影响

对基辅地铁中的钢轨缺陷进行的统计分析表明，发生大多数缺陷的主要原因是钢轨材料的接触疲劳。本文介绍了轨头裂纹扩展的现代概念。已经发现，研究轨道的应力-应变状态和裂纹扩展过程的最有前途的方向之一是数值模拟，它给出了轨道与地铁机车车轮之间的接触相互作用的结果。在仿真过程中，以弹性公式解决了该问题。我们考虑了R50，R65和UIC60轨道轮廓，标准铁路车轮以及轮胎轮廓由Minetek封闭式股份公司开发的车轮。轮-轮相互作用的条件对应于火车在轨道的直线部分上的运动而不打滑。已经评估了轮辋轮廓对不同类型的轨道中的接触应力水平的影响。比较不同轨道和车轮类型组合的最大等效应力水平，可以发现，地铁轨道直线段的最佳组合（就降低接触应力水平而言）是R50轨道，其坡度为20分之一和十分之一的锥形轮，其轮廓对应于GOST 9036-88。当使用Minetek公司开发的具有轮廓的车轮时，所有导轨类型的接触区中的最大等效应力水平都超过1000 MPa。高于钢轨的屈服强度，