Effect of rail grinding on rolling contact fatigue in railway rail used in conventional line in Japan

Effect of rail grinding on the rolling contact fatigue in conventional railway rail used in commuter line was investigated by means of metallographic observation, crystal orientation analysis by axis density measurement with X-ray diffraction, and EBSP analysis. Grinding was carried out twice to obtain a series of test rails with different grinding history. The metallographic observation confirmed that the rail grinding directly removes the plastic flow layer at the running surface of rail. Furthermore, examinations on the variation of the 1 1 1 axis density in the direction of depth and EBSP orientation map of the test rails show that the rail grinding seems not only to remove the fatigue of influence caused by the rolling contact with wheel and accumulated at the surface but to moderate them even at the inner position below the running surface although the action of the grinding does not directly attack at the area.