PROBLEM TO BE SOLVED: To shorten a cooling time and improve an execution property while maintaining the strength of a thermite weld zone and also to improve characteristics and performance, in particular, the fatigue strength of the thermite weld zone, in a thermite welding method for a rail.
SOLUTION: A reinforcement 4 of weld in the rail weld zone head 1 is removed after thermite welding, the rail weld zone head 1 is air-cooled by a wind pressure of ≥0.25 kPa to ≤4.90 kPa at a cooling speed faster than a temperature dropping speed of a rail weld zone bottom 3 until at least a temperature of the upper surface of the rail weld zone head 1 becomes 400°C from a time point when the central part 5 of the rail weld zone head 1 holds a temperature not lower than an austenite transforming temperature owing to residual welding heat. At this time, a rail weld zone body part 2 and the bottom 3 are mainly naturally cooled. Water cooling is performed after air cooling. Thus, the cooling time is shortened and also the fatigue strength is improved by positioning the residual stress of the rail weld zone bottom 3 nearer to the compression side.