Use of Magnetic Flux Techniques to Detect Wheel Tread Damage

Rail vehicle wheelsets are regularly maintained to ensure safe operation on track and prolong
life. This is achieved through measurements to inspect roundness, profile shape, rim thickness
and visual inspections of surface damage. If necessary, wheels are reprofiled on a lathe to
preserve the optimal wheel shape and remove any visible surface damage.
Surface damage is difficult to classify visually, leading to highly subjective results. It is also not
possible to establish defect depth through visual inspections. Magnetic flux leakage technology
has been successfully applied to the detection of defects in rails. This technology has been
adapted for the evaluation of wheel damage resulting in a fast, repeatable method of quantifying
damage on railway wheels.
This paper describes the theory behind the magnetic flux leakage technique and how it has
been applied to the detection of wheel damage. This includes a summary of the assessment of
the depth of damage into the wheel tread for a range of wheelsets. The benefits to train
operators of adopting this technology is also presented.