Abstract: After working on line six months or so,the 115RE rail has 220 mm-length longitudinal crack in waist. By macro-analysis to the damage rail,micro-analysis the sampling from crack source region by the stereoscan and the metalloscope,and checking the related mechanical property,the results indicates that the rail’s material is normal in quality,and the cracks occur from the bigger stress concentration in the bottom of rail-waist’s batch number “2” letter trace.