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On the UK rail network, changing usage patterns have led to rolling contact fatigue (RCF) on the railhead being an increasing problem and frequent testing for such defects is essential. Existing systems for detecting defects are limited in speed (< 30 mph) and accuracy (> 5 mm). We are currently working on novel ultrasonic methods of detecting RCF, designed to lift many of the speed limitations and/or significantly improve accuracy and resolution. A non-contact pitch-catch pulsed ultrasonic system comprising two electromagnetic acoustic transducers (EMATs) generating and detecting Rayleigh-like waves has the potential to operate at high speed, thus improving network inspection coverage. Phased array ultrasonic techniques are being designed to improve imaging and characterisation of the defects. A set of simulated defects on sections of rail have been machined, including half-face slots machined normal to the railhead surface, clusters of angled slots, and pocket defects more typical of real defects. The techniques have been tested on these rails and their potential for use on the rail network is discussed. [ABSTRACT FROM AUTHOR]

This paper describes research undertaken to understand the influence of vehicle dynamic response in the formation of Rolling Contact Fatigue (RCF) in rails. The use of both quasi-static curving simulation and detailed dynamic simulations are described. Site-specific Vampare® dynamic simulations for a range of vehicles and wheel profiles are compared with the actual incidence of RCF at the sites. Good agreement was found between variations in the wheel/rail contact conditions and the presence of RCF through the site. This not only allows the underlying causes of the RCF at the specific sites to be identified with confidence, but also sheds light on the mechanisms causing RCF on the UK rail network. [ABSTRACT FROM AUTHOR]