The surface of railway wheels running on rails is subject to damage due to rail and frictional wear, damage from wheel tread and flange wear caused by curved track operations, and damage from flats and concave wear due to braking friction heat from brake shoes. Although the surface of wheels is regularly reprofiled through periodic grinding cycles, damage occurring to the wheel surface during operation can lead to deteriorated ride quality and potential failure due to crack propagation. In domestic railway components technical standards, wheel integrity is mandated to be demonstrated through non-destructive testing. To prevent and detect failures caused by damage occurring on railway wheels, it is necessary to develop methods that could detect and evaluate surface damage. The present study investigated a method for detecting and evaluating surface damage on railway wheels using electromagnetic imaging. Results demonstrated that defects with a length of 10 mm, a width of 0.8 to 1.0 mm, and a depth of 0.2 to 1.0 mm could be adequately detected using electromagnetic scan images.

The repeated thermal load on the railway wheel for tread brakes has been remarkably tightened due to increase in speed of trains and increase of operation frequency. As overheating and cooling between the wheel and brake block are continuously repeated, the railway wheel is damaged. To understand the process, thermal cracks for wheel tread can be experimentally reproduced under the condition of cyclic frictional heat from brake blocks, through bench experiments using a railway wheel. Thermal cracks generated in the wheel were investigated to observe the cracks’ initiation processes using full-scale brake dynamometer. Results show that as braking energy and braking temperature continued to accumulate, a hot spot appeared on the wheel surface and 2 mm of thermal crack occurred in the wheel rim.