Local rolling contact fatigue and indentations on high-speed railway wheels: Observations and numerical simulations

Local rolling contact fatigue (LRCF) has occasionally been observed on wheels of high-speed electrical multiple units (EMUs) in recent years in China. It typically propagates to 2.5-8.5 mm deep along shallow angles to the tread surface, leading to large material removal during lathe turning. To reveal the initiation and propagation mechanisms of LRCF, a thorough investigation has been conducted by means of field observations, statistical analyses, and numerical simulations. It is found that 69% of LRCF occurred on the leading axles of leading coaches, and its occurrence rate on the 380 km/h class EMU was 2.87 times that on the 250 km/h class. Records of a 380 km/h class EMU train have shown that LRCF initiated with an occurrence rate of 14.3% from indentations of 2.3-3.0 mm deep and 4 mm in diameter, and the crack depth increased by 0.011-0.031 mm every 1000 km. All these phenomena, among others, suggest that indentations are the main causes of LRCF. The cracks, according to 3D transient and 2D static simulations of wheel-rail rolling contact, probably initiate at the bottom of deep indentations with a characteristic dimension longer than 2-4 mm. Preventive measures against LRCF are recommended at the end.