The effect of rolling contact fatigue mitigation measures on wheel wear and rail fatigue

The maintenance costs associated with heavy haul operations are mainly driven by wheel and rail damage in the form of wear and rolling contact fatigue (RCF). RCF initiated on the surface of the rail is the dominant damage mode on South Africa's iron ore export line. Two potential rail RCF mitigation measures were adapted from service tests and those published in literature and studied. The mitigation measures involved changes in suspension stiffness in an attempt to spread wheel wear across the tread and changes in rail profile design. These mitigation measures were evaluated by means of multi-body dynamics simulations including wheel wear predictions. Changes in suspension stiffness and rail profile design caused concentrated hollow wear on the wheels. These worn shapes of the wheels are conducive to RCF initiation with the worst performance coming from the application of a rail profile with gauge corner relief. Contact between the gauge side false flange of the wheel and the relief section of the rail profile were shown to increase the probability of RCF initiation.