The Influence of Wheel/Rail Contact Conditions on the Microstructure and Hardness of Railway Wheels

Figure 5

Orientation of leading wheelset on left and right hand curves, showing position of wheel/rail contact, direction of tangential force, and formation of two bands of cracks. The cracks near the flange of the wheel tend to be forced closed before contacting the rail and do not tend to propagate deep into the wheel. In contrast, the cracks near the field side of the wheel are forced open before they contact the rail; fluid entrapment and pressurisation in the contact can propagate these cracks into the underlying material.