Theoretical and Experimental Research on the Influence and Optimization Method of the 60N Profile in Turnout

This research elucidates the influence of the 60N rail profile on the dynamic interaction between wheel and rail, and the dynamic performance within the turnout. The influence of the 60N profile on the long-term service efficiency of turnouts was scrutinized. Subsequently, an optimization approach for the 60-60N rail combination profile was suggested. The main conclusions are as follows: (1) During the passage in the main direction, the 60N rail profile enhances driving stability and mitigates the progression of wear. However, it causes focalized wheel-rail contact on the rail head and escalates contact stress. (2) During the passage in the branch direction, the 60N rail profile amplifies the lateral dynamic force and rail wear rate in the closure panel, engendering two-point contact and increased contact stress. (3) In the early stage of field service of turnouts, a robust correlation exists between the contact band and the rail profile. In the fragile cross-section of the point rail, the contact band of the 60N rail profile turnout fully occupies the rail head, potentially causing stress concentration on the non-working edge position. By the stable service period, the wheel-rail contact band is mainly influenced by total weight. (4) An optimization method for the 60-60N combination profile was proposed with the corresponding machining tool profile designed. This strategy can avoid the profile transition before and after the turnout, reduce field maintenance workload, enhance running stability of straight passage through the turnout, and preclude fatigue damage in the weak cross-sections of the point rail.