Overview of fatigue damage evaluation rule for railway axles in Japan and fatigue property of railway axle made of medium carbon steel

Fatigue-limit-based designs were employed for railway axles in Japan, and new strength design and evaluation rules were developed to achieve more reasonable designs. Design specifications for strength were introduced to describe the detailed processes, whereas other specifications were introduced to propose a method for the estimation of the fatigue damage caused by variations in in-service conditions. Further, safety assessments were implemented by comparing the equivalent stress with the reference values obtained from past safe-operation records. The proposed assessment method is superior to previously used techniques for railway axles because of its low safety risk. To clarify the S-N curve of axles, full-scale fatigue tests were performed on railway axles used in Japan. The slopes of the S-N curve were specified in the damage evaluation rules.