# Experimental Research on the Load Transfer Mechanism of Tie Plates for 400 km/h High-Speed Turnouts
## 2 Materials and Methods
### Design of Experiments
#### 2.2.1 Experiment of Integral Stiffness of Plate Structure  
Experiment 1 conditions: a cover plate + a rubber washer + the original high-speed turnout universal tie plate. Experiment 2 conditions: a cover plate + the new high-speed turnout all-encapsulated universal tie plate with a rubber boss. In Experimental conditions 1, the tie plate was assembled, as shown in Figure 5a. The rubber-washer side of the cover plate was placed face down and pressed on the tie plate, with the hole aligning with the center of the steel sleeve; above the cover plate, a round tool was set to simulate the track spike, and a vertical loading device was connected to this tool. The other end of the universal tie plate was pressed by a pressing plate, and the bolt fixing the pressing plate was tightly secured to prevent the tie plate from tilting at one end during the experiment. Figure 3: Comparison of the force transmission paths of the two tie-plate structures: structures of the (**a**) original and (**b**) new tie plates. plate was under a force of 20 N; at this point, the applied load and displacement were reset. Vertical displacement was applied continuously until the universal tie plate was compressed for 3-5 mm vertically, and during this process, the applied load and displacement curve were recorded. The stiffness characteristics of the rubber washer and rubber boss and the forces transferred to tie plate through the rubber washer or rubber boss after the cover plate came into contact with the steel sleeve cannot be obtained. To overcome this shortcoming, a supplementary experiment was performed in Experiment 2. In field installation, the precompression of the tie plate under the rated torque of the tie plate bolt will have a considerable effect on the stiffness characteristics of the tie plate. Hence, the compressions of the tie plate under different loads are usually the key indicators of concern. However, in this experiment, the tie plate compression itself is unknown because the displacement recorded is the actual displacement of the cover plate. This value includes the compression of the rubber washer or rubber boss, steel sleeve deflection, tie plate compression, and other components. To overcome this shortcoming, a supplementary experiment was performed in Experiment 3. 2.2 Experiment of Stiffness of Rubber Washer/Rubber Boss after Cover Plate Contact with Steel Sleeve  
To make up for the shortcomings of Experiment 1 and to obtain the stiffness characteristics of the rubber washer and rubber boss after the cover plate came into contact with the steel sleeve, Experiment 2 was performed. During Experiment 2, the rubber washer and rubber boss were loaded separately, and the stiffness curves of the rubber washer and rubber boss during the whole loading processes were tested separately. Experimental conditions 3: a cover plate + a rubber washer + the original high-speed turnout universal tie plate. Experimental conditions 4: a cover plate + the new high-speed turnout all-encapsulated universal tie plate with rubber boss. In Experimental conditions 3, the tie plate was assembled, as shown in Figure 6a. The rubber-washer side of the cover plate was placed face down with one rubber washer pressed on the tie plate, and the cover plate was not in contact with the steel sleeve. The round tool was set above to connect with the vertical loading device. The other end of the tie plate was pressed by a pressing plate, and the bolt fixing the pressing plate was tightly secured to prevent the tie plate from tilting at one end during the experiment. A displacement meter was installed to measure the displacement of the washer below the cover plate. During the experiment, the assembly was subjected to displacement control, and the rubber washer was considered to be in contact with the tie plate when the cover plate was under a force of 20 N. At this point, the applied load and displacement were reset.