Abstract
The terrible derailment accident happened in a Japanese metro in spring, 2000. The accident investigation committee established by the government pointed out several causes of the flange climb derailment which means that a wheel flange climbs up the gauge corner of a high rail usually at sharp curves. One of most difficult causes to understand its characteristics was the coefficient of friction. Measurements of friction coefficient of rails were carried out at 20 track sites. In this paper, the influence of operational frequency of trains, humidity and some other parameters on friction coefficient are described.
