Method and criteria for evaluation of wheel derailment based on wheel vertical rise

After comparing the worldwide commonly used evaluation criteria for wheel derailment with that given in the China's national standard, GB 5599—85, some limitations were pointed out in the paper. A principle and the method were then proposed to evaluate the wheel derailment based on the variation of wheel vertical rise. Wheel derailment courses were simulated both for a single wheelset derailment and for a full scale vehicle derailment from the point of view of vehicle track coupling dynamics. Results obtained show that if the wheel vertical rise height is smaller than the wheel flange height, the wheel derailment can be avoided, no matter whether the derailment coefficient (Q/P) is larger than the Nadal value or not. A proposed derailment criterion for evaluation of railway vehicle safety is given in the last part of the paper.