Experience in maintaining railtrack in Japan

You are here: Homepage > Search

Experience in maintaining railtrack in Japan

Fukuda, Y. / Yamamoto, R.I. / Harasawa, H. / Nakanowatari, H.

This paper describes the state of the art concerning the welding processes for continuous welded rail (CWR) in maintaining rail track in Japan and the reliability of rail welds. In order to extend the service life of CWR, it is important to perform reliable welding for joints by utilizing appropriate welding processes, inspection methods and well-trained welding personnel. It is known that flash welding (FW) and aluminothermic welding (TW) are commonly used in the world. On the other hand, gas pressure welding (GP) and enclosed arc welding (EA) have progressively been expanded in Japan. Both welding processes have been contributing much to the high-speed tracks of SHINKANSEN (bullet trains in Japan) since 1964. Features of GP and EA, originally developed in Japan, are introduced including characteristics of equipment, productivity of process, mechanical properties of weld and welding procedure for head hardened rails. Recent topics of process developments are also introduced, such as the semiautomatic process in enclosed arc welding. As partial depression is formed by wear at welds in CWR, its surface irregularity increases the dynamic wheel bad, resulting in the rail bending fatigue failure. Therefore, rail surface grinding is periodically performed in order to prevent the rail bending fatigue failure as well as to extend the rail service life.The number of rail weld failures has gradually decreased, since an improved inspection method is applied right after welding. A maintainance flowchart to detect and eliminate surface irregularities is presented.