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British Rail Research, P.O. Box 2, London Road, Derby DE2 8YB (7J.K.j Abstract Contact stresses between wheel and rail are believed to be influential in the initiation and growth of rolling contact fatigue cracks, particularly on the high rails of curves on high speed lines. A modification to the transverse rail profile has been proposed which should result in reductions in contact stress. Theoretical methods have been used to investigate the effect of pro6le changes on contact stress and conicity. The predicted contact stresses for the modified profile are up to 50% lower than those for an unused standard British Railways (BR) profile whilst the conicity remains within an acceptable range. The metal removal required to achieve this profile appears practical using the latest generation of more aggressive grinding trams. 1. Introdu ction On curved track the outer rail is laid higher than the inner rail. This outer or “high” rail has been found to be susceptible to rolling contact fatigue (RCF), resulting in the initiation of cracks from the running surface of the rail. These shallow cracks can develop into squats [l] which can either (i) link together, resulting in the loss of surface material, or (ii) turn and propagate transversely through the rail. Extensive laboratory work [2, 31 has been carried out to investigate the factors influencing the generation of rolling-sliding contact fatigue cracks (using testing equipment that simulates wheel-rail interactions). It was reported that both contact stress and creepage have a significant effect on RCF life. The following relationship was derived: RCF life aP,,” (I) where PO is the maximum hertzian contact stress and n is a constant dependent on creepage (-4.2n -1.8). Further research is currently being undertaken at Leicester University [4] into wheel-rail crack initiation, one of the aims being to determine a fatigue limit for RCF. This paper describes a method for reducing contact stresses between wheel and rail in or