Synopsis Soon after the October 2000 rail disaster at Hatfield, a number of rail maintenance and rail accident research centres throughout UK, Europe and North America, initiated new rail testing methods to identify and evaluate the phenomena of Rolling Contact Fatigue (RCF), which was the cause of the rail shatter in Hatfield. In November 2000, Harsco Track Technologies, a reputable American rail maintenance company in partnership with Balfour Beatty Rail Projects upgraded a mothballed Rail Flaw Detection train (RFD which was manufactured to inspect the Channel Tunnel tracks in previous years, to inspect the rail infrastructure in UK for potential rail breaks due to RCF and other rail defects. Initially recruited by Harsco Track Technologies and due to almost 20 years of experience in ultrasonic and various other NDT methods, I headed the Rail Flaw Detection team for Harsco Track Technologies and trained up as a chief ultrasonic operator of the RFD system, the training involved 1200 miles of rail testing in eight states of America together with lab based rail defect analysis.. Armed with new skills and competencies and back in UK, we set about testing the tracks for Railtrack. In over 2 years of rail inspection throughout the country, by the end of the project over 1600 reportable defects were identified and remedied. However the due to the orientation and the characteristics of the RCFs the ultrasonic testing methods proved to be an insufficient tool, the reason behind this method failure, was the over population and the density of the Gauge Corner Cracks (GCC), in that the parallel type cracks on the gauge side of the rail were masking the sound paths hence giving rise to spurious indications rather than useful defect recognition. In the summer of 2002 Railtrack (The infrastructure owners) decided to end the ultrasonic RFD project and focus on a more accurate and systematic method to detect and quantify the sizes of RCF cracks. This time Balfour Beatty and a UK based company (TSC) that had just finished the manufacturing of a new electromagnetic system called ACFM went into partnership to concentrate on the inspection of chosen RCF sites by the collaboration of permanent way Engineers and manager, where I was duly appointed as a team leader to carry out the trails of the new system, for this new inspection regime my team and I were trained by the manufacturers of the equipment and gained the appropriate accredited qualifications from the Welding Institute. In September 2002 a number of RCF trial sites were allocated and the inspection of these sites began in earnest, once again due to a large number of crack population aligned close to each other, it was noted that the processing system of the ACFM unit failed to cope with the incoming information at such a fast rate. In order to rectify this problem, results of several sites were analysed and a decision was made to filter out the non-detrimental cracks and leave room on the data recorder of the equipment for large defects with a greater pocket length. Further investigative tests on RFC sites revealed that some of the cracks also harbour a more sinister defect that could cause a rail break, to evaluate this category of defect a combined ultrasonic and electromagnetic system is being developed as part of my PhD and the proposal will be published in July 2009.