Numerical investigation of dynamic derailment behavior of railway vehicle when passing through a turnout

Wheel flange climb derailment of vehicles in railway turnouts is a serious safety issue. In particular, derailment accidents in smaller turnouts, caused by poor track alignment before the turnout or structural degradation, are becoming more and more frequent. Most of the previous research on derailment has focused on main track areas, while the dynamic derailment mechanism for turnouts is still not clear. For this reason, a field derailment investigation of freight wagons in No.6 symmetrical turnouts is presented in this paper. Taking this into consideration, a half-car multi-body dynamics model and flexible turnout model, subject to wheel flange climb derailment, has been established. In addition, a field test for wheel-rail interaction was carried out to verify the dynamic model. This model is capable of revealing derailment evolution of the front and rear wheelset for a bogie under critical derailment conditions. The influence of several sensitive parameters of the derailment model on critical derailment behavior has been carried out. Results show that the simulation results of the wheel climb derailment are very consistent with the filed investigation, and the safety of the bogie depends on the status of both front and rear wheelset. This work is a world first in providing a solid understanding of dynamic derailment behavior and motion posture, giving guidance on the prevention of wheel flange derailment in turnout areas.