A railway project co-funded by the UK’s innovation agency, the Technology Strategy Board, called RailSAFT has been successfully completed. The consortium is pleased to report the successful development and implementation of an ultrasonic technique capable of reliable inspection of cast high-manganese steel railway crossings. The developed system utilises a combination of low-frequency ultrasonic transducers and a post-processing image reconstruction technique known as Synthetic Aperture Focussing Technique (SAFT). The system has been shown to reliably detect and locate real sub-surface and surface breaking defects in critical regions of manganese steel crossings.
Cast high-manganese steel railway crossings are employed at safety critical locations throughout the UK and European railway infrastructure due to their work hardening material properties. Repetitive high velocity collisions from rolling stock, act as a catalyst for fatigue cracking which can compromise the structural integrity of such components. Due to the fully austenitic coarse grained structure of cast manganese steel crossings, examination of the material sub-surface is ineffective using current industry standard ultrasonic techniques.
Inspection of in-service crossings is limited to visual and dye-penetrant surface inspection. With no practical sub-surface inspection method available, the structural integrity of in-service crossings remains unknown, resulting in conservative service life estimates and high life cycle costs for railway operators and infrastructure owners.