Influence of guide curve spatial alignment on train-turnout dynamic interaction in 1:42 turnout

This paper investigates the spatial alignment of a 1:42 high-speed turnout during diverging operations. A kinematically coupled alignment method is proposed, in which the parameters of the superelevation transition are determined from the corresponding horizontal-alignment parameters. This allows the curvature evolution and superelevation variation to be coordinated within a unified three-dimensional framework. The method combines superelevation, higher-order transition curves, and a transition-transition configuration in which the constant-curvature circular segment is replaced by a transition curve. The existing alignment and four modified configurations are evaluated using a verified vehicle-turnout coupled dynamic model at 160 km/h and the simulated target speed of 200 km/h. The results show that superelevation reduces the sustained lateral wheel-rail force and derailment coefficient during the post-peak decline phase. The transition-transition configurations may produce slightly higher instantaneous peaks at 160 km/h, but limit the growth of dynamic responses as speed increases. At 200 km/h, these configurations reduce the peak lateral wheel-rail force, derailment coefficient, vertical wheel-rail force, wheel-load reduction rate, and car-body lateral acceleration. The seventh-order-seventh-order (7th-7th) configuration provides the most favourable performance. The results indicate that the proposed spatial alignment method has the potential to support diverging operations at 200 km/h.