Dynamic matching design method of horizontal curves for 400 km/h high-speed railways

Continuous increase in high-speed railway operational speeds up to 400 km/h imposes ever-stricter requirements on the horizontal curve design. Consequently, the applicability of conventional track alignment design approaches grounded in simplified point-mass kinematics warrants systematic re-examination. To this end, this paper presents a methodology for the dynamic matching design method of horizontal curves for 400 km/h high-speed railways based on vehicle-track coupled dynamics. First, a quasi-dynamic method (QDM) is employed to simulate a stationary vehicle on a curved track. The superelevation is gradually increased from zero to a large value within a prescribed simulation time, and an explicit numerical integration is utilized to solve the quasi-dynamic governing equations. The critical warning superelevation and overturning superelevation are identified by evaluating the derailment coefficient, wheel load reduction rate, and wheelset lateral displacement under different track models, vehicle loads and wheel-rail friction coefficients. Second, dynamic matching relationships among curve radius ( R ), superelevation (Δ h ), and cant change rate ( f ) are fully investigated by evaluating the influence of various combinations on running safety and ride comfort. Given that the cant change rate has a negligible influence on the R -Δ h matching relationship, the discussed range is further extended up to 200 mm/s to identify the corresponding critical threshold. The research results indicate that, under the computational conditions adopted in this study, a maximum cant change rate of 60 mm/s remains applicable to 400 km/h high-speed railway curve design, which is notably higher than the 25∼31 mm/s specified in current Chinese standards.