Abstract
In this study, the existing inspection and adjustment method of rail joint gap is evaluated by comparing the degree of danger calculated from the existing method with that calculated from the computer simulation using the Monte Carlo method. In conclusion, it can be verified that the degree of danger calculated from the existing method is sufficiently reliable in the range of dangerous area where the risk of track buckling (sun kink) is very high. It can also be indicated theoretically that after the existing method was introduced to JNR track maintenance, probability of occurring of track buckling has been drastically reduced.