Railroads Surface Crack detection using Active Thermography

Rails are basic mode of transportation all over the world. In-service railway lines are inspected for cracks on a prescribed frequency for damage diagnostics. The conventional methods of cracks detection of such large structure are either semi- automated or manual which make inspection process time consuming. Non-destructive testing utilizing infrared thermography has been proven additionally useful in structural health monitoring of various structures. Active thermography for the surface crack inspection of railroads is another potential application under exploration. In this work, lateral surface cracks of various dimensions are created on an in-service railroad. Railroad was uniformly heated to temperatures matching the practical conditions. For the crack detection, infrared camera was used to record the infrared radiation which were emitted as a result of applied thermal stimulus on rail road surface. As the surface temperature rises above the ambient condition, the railroad defects became prominent. Subsequently, post-processing was performed on raw infrared images to evaluate the results quantitively. The developed system will provide a robust and inexpensive solution for railway/highway authorities and NDT companies for damage diagnosis.