Influence of wheelset rotational motion on train collision response and wheelset lift mechanism

When a train is in a nonbraking state during an actual collision, the wheelset rotational movement aggravates the wheel–rail impact and increases the wheel lift and risk of overriding. Based on the principle of equal initial collision kinetic energy, the idea of using wheelset translation instead of rotation is proposed. Moreover, the calculation formula for a mass equivalent coefficient is deduced. From the perspective of the dynamic transmission relationship between the car body, bogie, and wheelset, the mechanism of the wheelset lift are investigated. The research results show that without considering the rotational kinetic energy of wheelset, the difference of collision response can be effectively reduced by increasing the translational mass of wheelset by 10%. The vertical speed lift displacement and inclined lift displacement of the bogie have the largest contribution to the wheel lift. When the wheelset rotation is not considered, the wheel lift is significantly reduced.