Investigation of rolling contact fatigue cracks in a grade 900A rail steel of a metro track

Rolling contact fatigue (RCF) has been of increasing concern in the recent years in respect of the safe operation of high-speed railway track with high traffic intensity. The present paper summarizes the results of the first investigation of RCF damage encountered in the Athens Metro. The objective of the investigation was to determine the initiation and propagation of RCF cracks and to determine their geometrical characteristics. A thorough metallographic investigation of track regarding shelling and spalling defects showed the development of a subsurface network of cracks. An analysis of the Hertzian stress field was used to determine the conditions for first yield and shakedown limits as a function of loading