Objective To analyze the contact problem of wheel / rail with surface crack. Methods Using the finite element analysis software ANSYS, stress intensity factors at the crack tip on rail surface were obtained for different locations of crack. Results The stress intensity factor K_I reached its maximum when the location of crack was at the edge of the contact area. The stress intensity factor K_I increased with the increase of axle load, but the stress intensity factor K_II first increased and then decreased. When the friction ( μ = 0 . 3 ) was taken into account, both the K_I and K_II increased significantly as compared to the calculation excluding friction, and the proportion of K_II in K_I increased by 15 % . Conclusion When the wheel is pure rolling on the rail, both the axle load and the friction are important factors affecting the fatigue of the rail . The increase of axle load leads to significant increase in rail fatigue, while the friction intensifies the effect of axle load on the rail fatigue since the influence of friction is based on the axle load.