The European rail network is getting more and more predominant in the transportation sector: it hosts high speed-trains, higher loads of more passengers or goods, with increased frequency. This determines a higher mechanical load for the moving parts of the carrier involved: therefore, increasing inspection and maintenance are required to guarantee the safety and well-being of trains. One of the biggest concerns about transportation safety is broken wheels due to internal cracks. Frequent accidents and regular breakdowns have been registered in the latest years due to this failure. Three testing methods have been investigated and simulated to identify cracks or problems on the surface or near the surface of the wheel: Magnetic Particle Inspection, Dye Penetrant Inspection, and eddy current testing. These methods show the following drawbacks: MPI and DPI generate a high amount of hazardous waste and none of them is automatable, while the eddy current system is sensitive to lift-off variations and probes need to be positioned at a constant distance. In conclusion, a new, more efficient, automated and faster method is needed to detect surface cracks.
