Detection of White Layer on Rail by Using SQUID

White layers, which often cause a break of a rail, are generated on its top surface when train wheels spin on it. Therefore its early detection of damaged conditions of the rail that may lead to a break is a critical activity in the rail maintenance. In this study, we have developed an effective method to detect the white layer on the top surface of the rail by using a Superconducting Quantum Interference Device (SQUID).