I. General
1. The bending fatigue test for the rail is conducted to obtain the fatigue curve and fatigue limit of the rail under alternating stress.
2. During the test, the rail is simply supported on two bearings with a support span of 1,000mm, its rail head being upward, and its concentrated load applied to the midpoint of the span.
3. The radius of the indenter running surface curve applied with load is 420±5mm, and the width of the running surface (perpendicular to the rail length) shall be greater than that of the rail head. The indenter hardness is HRC 50~60, and the surface finish is not less than 4.
4. The rail stress may be calculated according to the following Equation:
