Comparative Structural and Fatigue Analysis of R260 and R350HT Rail Steels Under High-Speed Dynamic Loading

Repeated wheel–rail interaction under millions of load cycles causes rolling contact fatigue, plastic deformation, and long-term rail degradation. Increasing axle loads, speeds, and traffic demand require an understanding of how rail steels respond under dynamic loading. This study compares the mechanical and fatigue behaviour of R260 and R350HT rail steels using a three-dimensional finite element model of a UC-515 wheel rolling over a UIC-60 rail. Symmetric boundary conditions were used to reduce the computational cost without affecting accuracy. Wheel loads of 50–150 kN and speeds of 50–300 km/h were considered, with elastoplastic behaviour assigned to the rail and substructures. The predicted Hertzian contact pressures were analytically validated, and the resulting stress fields and equivalent plastic strain distributions were used for fatigue assessment. Fatigue life and cumulative damage were evaluated in fe-safe using the Brown–Miller criterion. R260 developed larger plastic zones and higher stress amplitudes than R350HT at higher speeds. Multipass simulations indicated a reduction in fatigue life and higher damage accumulation for R260 above 150–200 km/h beyond certain passes. Conversely, R350HT accumulated damage more slowly due to higher strength and hardness. The framework provides a comparative basis for assessing fatigue crack initiation tendency rather than predicting absolute field life.