# Experimental Research on the Load Transfer Mechanism of Tie Plates for 400 km/h High-Speed Turnouts
## 3 Discussion and Conclusions
### Conclusions  
In this paper, optimized structure of elastic tie plate for 400 km/h high-speed turnout are put forward. The main structural characteristics of new plate are as follows. 1. Side encapsulation is extended to the rail groove on the upper surface of the elastic iron tie plate to solve the cracking of the side encapsulation of the existing elastic iron tie plate. 2. A rubber boss is set on the vulcanized layer on the upper surface of the tie plate to replace the rubber washer on the lower surface of the cover plate, and the round hole on the cover plate used for installing the rubber washer is canceled. Thus, the problem of rubber washer failure can be solved. 3. The structure and size of the rubber block on the lower surface of the elastic iron tie plate are modified to adjust the stiffness. 4. The second-order stiffness structure design is adopted for the elastic iron tie plate to ensure the safe running of the vehicle. 5. A sinking design is adopted for the perimeter rubber of the steel sleeve, which is vulcanized into a whole with a 2 mm encapsulation layer on the tie plate to improve the sealing performance and to avoid the rubber from being damaged because of outward bulging. In addition, systematical experimental research works are conducted to quantitatively compare and analyze the overall stiffness characteristics of different tie-plate structures and the differences in bolt force transmission and distribution laws. The following conclusions can be drawn:  
1. The laws of vertical load transfer and distribution in the new tie plate are remarkably different from those for the original tie plate because of the differences in their structures. 2. Under the rated bolt torque, the force transferred to the upper surface of the tie plate through the rubber boss in the new tie plate is less than that in the original tie-plate structure by 5.18 kN in the assembled state. Further, the new structure also has lower tie plate precompression, and hence, the influence on the stiffness characteristics of the tie plate is less than that in the original structure. However, the steel sleeve deflection in the new tie plate is greater than that in the original tie plate; that is, a larger proportion of the bolt preload force is borne by the steel sleeve, thus making the vulcanized rubber under the steel sleeve more vulnerable to shear damage. 3. If put into actual use, the tie plate bolt torque will be somewhat different from the rated torque; because of the difference in the torques coupled with the different vertical load transfer mechanisms between the new and the original tie-plate structures, the precompression and the proportion of the bolt preload force borne by the steel sleeves of the two tie plates will also show the different degrees of deviation corresponding to different deviations of the tie plate bolt torque. The stiffness of the rubber boss is larger than the rubber washer. However, the main advantage of the rubber boss is that the surface of iron plate can be protected by rubber so as to reduce the problems of corrosion, glue failure, etc. In addition, in the service process of the existing high speed turnout, the rubber washer fails easily, and the structure of cover plate is too complex for the installation of rubber washer. The above problems can be solved well by replacing the rubber washer with the structure of rubber boss. Therefore, the new tie plate structure needs to be further optimized to make the transfer mechanism of preload force of bolt as consistent with the original tie plate as possible. In the future work, the vibration and deformation characteristics and long-term service performance of the new type of plate under the condition of vehicle passing will be studied through a small-scale field trial and systematic dynamic tests, which includes the test of dynamic stiffness and other indexes. **Author Contributions:** Conceptualization, Z.S. ; methodology, P.W. ; validation, Z.Z. ; formal analysis, Z.S. ; investigation, Z.M. ; writing--original draft preparation, P.W.