Advanced real-time rail monitoring system based on directional eddy current probe

Increased train speeds and freight loads have contributed to the development of Rolling Contact Fatigue (RCF) and localized damage, such as studs and squats, at wheel-rail contact points. If left undetected, these defects can progress into shelling, where fluid penetration into fatigue cracks accelerates crack propagation and material separation or rail breaks. To address this issue and preserve rail integrity, a non-contact, high-speed, real-time directional eddy current probe for defect inspection has been developed. Initial laboratory testing of the portable prototype, conducted with studs exhibiting RCF-type defects, demonstrated successful detection at increasing speeds. The obtained eddy current results were further validated by ultrasonic testing (UT) to determine the depth profile. Finally, the signal-to-noise ratio (SNR) of the proposed system was estimated for a quantitative evaluation of inspection performance. Subsequent field tests were performed by integrating the technology with a Geismar TC Track Screwdriver on a section of R50 rail on track in the Almaty region of southern Kazakhstan. The system effectively identified spalling, indentations, and shelling defects, with a signal-to-noise ratio exceeding 4.5, showcasing its potential for reliable rail-defect inspection.