Fatigue failure of the railway axle, which has been a source of difficulty for engineers since railroad service started in the early part of the nineteenth century, was the beginning of the study of metal fatigue. In order to maintain the safety of a high-speed railway system, a large number of investigations and experiments have been carried out by outstanding researchers ever since, and many improvements have been made in the material, manufacturing, heat treatment and design methods. In comparing Japan and Europe on the fatigue design philosophy of the high-speed railway axle, it is recognized that there is a difference between the Japanese Shinkansen and the European TGV and ICE. The critical parts for fatigue strength are the press-fitted parts which suffer from fretting fatigue damage, such as the wheel seat, gear seat and brake disc seat. In Europe, the larger diameter of the press-fitted part makes the fillet the critical part. In Japan, however, the fatigue strength of the press-fitted part is increased by an induction hardening method. Also, a stress-relief groove is made at the closely press-fitted part of the axle. For several years, no fretting fatigue cracks in Shinkansen axles have been detected by magnetic particle inspection. It is noted that improvements over many years have been successful in achieving the safety of high-speed railway axles. These problems will be studied in this paper.
Short/small fatigue crack growth, thresholds and environmental effects: a tale of two engineering paradigms