Development of a Method of Continuously Detecting Transverse Cracks in Rail Heads

Transverse cracks (squats) occurring in rail heads are usually managed by ultrasonic detection from the rail top surface using an angle probe or by ultrasonic transmission detection where probes are placed on the gauge face and field face of the rail head. However, when there are defects such as large horizontal cracks or head checks on or under the rail surface, or when there is some deformation of the rail head due to wear and the like, those interfere with ultrasonic waves, resulting in insufficient defect detection. At the same time, to find internal defects that develop in a certain length of rail, it is also desirable in terms of improving detection efficiency to continuously detect such defects while moving in the direction longitudinal to the rails. In light of that situation, the authors have developed a new defect detecting device. The developed new device can continuously detect transverse cracks regardless of the rail head condition by using phased array technology where two probes send and receive ultrasonic waves at the upper fishing surfaces (underside of the rail head).