Assessing Impact of Wheel–Rail Force on Insufficient Displacement of Switch Rail in High-Speed Railway

High-speed railway turnouts play important roles in the efficient operation of trains. However, the complex mechanical structure of turnouts and insufficient displacement of switch rails under dynamic conditions create a point of vulnerability for high-speed railways. The insufficient displacement of switch rails in high-speed railway No. 18 turnouts critically impacts operational safety. This study establishes a coupled finite element model of the switch rail and sliding track bed plate to analyse the effects of the friction coefficient and wheel–rail force. The results show that without considering the force of the iron block, the maximum insufficient displacement of a switch rail occurs at sleeper No. 27, and the maximum insufficient displacement increases linearly with the friction coefficient, with a regression coefficient of 1.02. When considering the wheel–rail force of the train, the maximum insufficient displacement of the switch rail occurs at sleeper No. 25, with the regression coefficient reduced to 0.67. Through dynamic and static tests and a case analysis, the influence of wheel–rail force on the insufficient displacement of a switch rail is verified. The results show that the application of a lateral wheel–rail force in the model significantly reduces the insufficient displacement of the switch rail, with an improvement of more than 90%. This study can significantly improve the optimisation of turnout design and the operational efficiency of a railway network.