Analysis on dynamics performance of the existing wheel–rail high-speed railway raising to 400 km/h operation

The speed of 400 km/h represents a milestone that humanity has been striving for in wheel–rail high-speed railway systems, and the research is extremely challenging. By taking into consideration the elastic deformation and three-dimensional vibration of the rail, track slab, as well as the concrete base within the track structure, while simplifying the vehicle as a rigid body with 31 degrees of freedom, a sophisticated rigid–flexible combined dynamic model of the vehicle–track spatial nonlinear coupling system has been established. The “trace method” and the “minimum distance method” are employed to locate the wheel–rail spatial contact points, followed by the wheel–rail quasi-elastic contact correction. Subsequently, the geometric relationship of the wheel–rail spatial contact is constructed. Given the complexity of the dynamic problem of the vehicle–track spatial nonlinear coupling system and the time-consuming nature of searching for the wheel–rail spatial contact points, the cross-iteration algorithm has been improved and a novel numerical approach has been proposed. By integrating the “trace method” into the improved cross-iteration process, this approach significantly promotes both the computational efficiency and the model accuracy. As an application case, the adaptability of the existing high-speed railways in China to operate at a speed of up to 400 km/h under the excitation of track random irregularities is examined, and the dynamic characteristics of high-speed trains and slab track structures are explored by taking into account the rail local profile irregularities. The study shows that it is feasible to increase the operation speed of the existing CRTS II high-speed railways to 400 km/h, and the corresponding dynamic response indexes of the trains and track structures can satisfy the safety operation limits.