Wear of rails in turnouts is a common problem during the operation of high-speed railways. It can seriously affect the running safety of trains and the service lives of wheels and turnout rails. In this study, a numerical prediction model for rail wear development in high-speed railway turnouts was established. According to the material wear theory developed by Archard, the wear depth distribution in the wheel–rail contact patch was calculated based on a vehicle–turnout coupling dynamics simulation and wheel–rail rolling contact analysis. For the dynamics model, various components of the vehicle and complex nonlinear interactions between the components were simulated in detail to guarantee consistency with reality. The combination relationship of the switch and stock rails and the irregular and variable cross-sections of the rails in the switch panel of the turnout were considered. Spatial interpolation was used to achieve three-dimensional transitions between adjacent irregular cross-sections to model the compromised rails in the turnout. In addition, the stiffness and damping characteristics of the track in the turnout zone were taken into account. The rail wear rates for every characteristic section of the switch panel were calculated by the superposition model for rail profile wear. An adaptive-step algorithm was adopted in the iterative computations to update the rail profiles for every characteristic section position, which could reduce the cumulative errors and effectively improve the stability and reliability of the numerical model. Finally, case studies were conducted to investigate the wear developments of the switch and stock rails of high-speed turnouts using the developed model. In addition, the rail wear status of turnouts in the Shanghai–Nanjing high-speed railway was measured. The numerical prediction results are consistent with those of the actual situations in the field, verifying the rationality of the established model. This work shows the potential for guiding the maintenance and optimal design of turnouts and improving the understanding of the formation mechanism and influencing factors of rail wear in turnouts.

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To analyze the wheel-rail frictional rolling contact solutions and uneven wear in a switch panel, the wheel-rail frictional rolling contact model based on explicit integral algorithm considering coupling effect of structural vibration and contact mechanics, arbitrary contact geometry and nonlinear material is established. Then the wheel-rail explicit dynamics theory, unrepeatable saturated design, wear prediction method and data statistical processing methods are integrated as a method to figure out the key affecting factors, recognizing the influence of key factors on wheel-rail contact behavior and uneven wear in switch panel, including the contact force, the instantaneous and drastic changes of size, stress and microslip in contact patch and the distribution and magnitude of wear. The results of numerical simulations can provide guidance for investigation of contact mechanism and understanding of rail maintenance in switch panel.

Based on the necessity of optimizing the structure of No. 9 single turnouts of 60-kg/m rails, we addressed the issues associated with existing turnout switching design methods. Based on finite element analysis, we established a refined calculation model for turnout switching. The model can determine the plane alignment of a switch rail separated from the stock rail based on the actual force acting upon the switch rail. The obtained plane alignment is consistent with the actual situation and is thus reliable. Based on the established turnout switching model, the minimum flangeway width and dynamics between the strokes of the first and second traction points under different conditions were analyzed by numerical simulations. Accordingly, we propose an optimized scheme that takes 160 mm and 85 mm as the stroke value for the first and second traction points, respectively. The scheme helps to meet the requirements for minimum flangeway width while making the deformation of the switch rail more even and therefore minimizing the traction power. Based on the proposed design, trial production and laying of the new No. 9 single turnout with a 60-kg/m rail was conducted, and a switching test was performed. The switching forces at the first and second traction points of the new No. 9 turnout were approximately 1200 and 2000 N, respectively, which were higher than those of existing No. 9 turnouts with 60-kg/m steel rails. Besides, the minimum flangeway width satisfies the requirement for safe vehicle passage with a safety margin of 3–5 mm. The test results proved the effectiveness of the proposed turnout switching design method and parameter optimization scheme.

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