Model for analysis of bogie frame motion under derailment conditions based on full-scale running tests

Preventing railway vehicles from derailing is the most important earthquake countermeasure. Similarly, formulating measures to prevent vehicles from deviating from the track in the event of a derailment is an extremely important secondary measure for minimizing the risk of fatalities. The authors have developed a post-derailment stopper, which prevents derailed vehicles from veering off the track by catching on guard rails. We conducted running tests under derailment conditions using real bogies and tracks to develop the stopper and evaluate its efficacy. Since we observed peculiar motions of the bogie frame when the stopper was attached during running tests, we propose a 15 DOF vehicle dynamics model in order to discuss, in particular, the motion of the bogie frame and the stopper under derailment conditions. In this model, we give degrees of freedom to the motors mounted on the bogie frame because contact between the stopper and the guards was observed repeatedly during running tests. In addition, in this simulation of a derailed vehicle, static equilibrium conditions are calculated using the data obtained from running tests prior to the time history analysis. We evaluated the validity of the proposed model by comparing the calculated results with measured data.