Influence of Cross Wind on Derailment of Railway Vehicle Running on Curved Track at Low Speed

Due to the lightening of railway vehicles and the improvement of operation speeds, the reduction of running safety by cross winds is becoming an important problem. In particular, the running safety tends to reduce when the vehicles are running on curved sections. When a cross wind acts on the vehicle running on a curve from the outer side, a flange climbing phenomenon can occur. In this study, a full vehicle model was constructed using a multi-body software, SIMPACK, and the running simulation on a curve was carried out to examine the running safety under the condition that a cross wind acted on the vehicle from the outer side of the curve. As a result, it is verified that the derailment coefficient of the first wheelset becomes large in the exit transition curve and that of the third wheelset does in the entrance transition curve and this trend is pronounced by larger wind forces. Here, the derailment coefficients at the timing the derailment occurs are different between the first and third wheelsets, and those derailment coefficients are much larger than the critical derailment coefficients obtained by Nadal's formula. Then an equivalent friction coefficient which depends on an attack angle is introduced in Nadal's formula. Consequently, the critical derailment coefficient considering the equivalent friction coefficient came close to the actual derailment coefficient.