Influence of profile optimization on wear and fatigue characteristics of curved rail: An experimental study

This investigation introduces an optimization methodology for rail profiles designed to equilibrium rail wear and fatigue damage. An optimized rail profile for the R600 m curve was developed through the examination of numerous case studies. Concurrently, the impact of profile optimization on the wear and rolling contact fatigue of CHN75 railway was assessed using a twin-disc rolling contact test rig across a range of cycling numbers. The test results indicate that rail profile optimization can significantly enhance the wheel-rail contact condition, achieving a maximum reduction in rail wear of 31.6 % at the highest cycling number. Moreover, the optimization process increases the surface hardness of the rail, resulting in a 13.4 % decrease in the depth of the plastic deformation layer at peak cycling. With the progression of cycling numbers, both rail wear and fatigue damage intensify, and a black oxide layer forms on the rail surface. In the CHN75 rail test, once the cycling number surpasses 6 × 104, material spalling due to fatigue crack propagation removes the black oxide layer. Rail wear becomes the predominant mechanism when the cycling number exceeds 8 × 104, leading to the removal of both the black oxide layer and fatigue cracks. In contrast, the CHN75-OPTI rail test exhibited significantly reduced rates of wear and fatigue damage, thereby highlighting the efficacy of profile optimization in mitigating these issues.