Ultrasonic Flaw Detection Systems for Testing Rails in Iran Railways (RAI)

To have a safe and reliable railway system, nondestructive testing (NDT) methods are necessary to be implemented in order to avoid catastrophic failures. NDT methods also provide a powerful tool for proper maintenance of valuable railway system assets. Among various NDT methods, ultrasonic testing (UT) along with magnetic particle testing (MPT) and eddy current testing (ECT) play significant roles in testing rails, rail welds and other train parts and assemblies such as wheels, suspension system and bogie axles of rolling stocks. One of the vital sections of rail tracks are the weld joints for which two main methods of welding are currently being used in Iran railways (RAI); thermite welding and flash butt welding. Each of these methods has its own pros and cons. Penetrant testing (PT) along with UT are used to detect potential flaws in both the weld and rail. UT is used during construction of rails (at rail manufacturing site) and also during operation in certain time periods in order to detect internal cracks and any other flaws which might lead to a failure. In this paper, two ultrasonic flaw detectors currently used in RAI for inspecting rails are introduced. Results obtained from testing rails by these two flaw detectors are also briefly discussed.