WJ-7 Rail Fastening System

This fastener system is a shoulder-free elastic split structure with iron pads, with the following structural features:

a) There is no concrete shoulder in the concrete sleeper or track slab bearing groove, and a 1:40 rail bottom slope is set on the iron pad. The concrete sleeper or track slab bearing surface is a flat slope. It can be used for both sleeper (double-block sleeper, long sleeper) buried ballastless track and track slab ballastless track. The lateral load transmitted by the train is mainly overcome by the friction of the iron pad.

b) A rubber pad is set between the rail bottom and the iron pad to achieve the elasticity of the system. By replacing the rail pads with different stiffness, it can adapt to the operating conditions of 350 km/h passenger dedicated line and 250 km/h passenger dedicated line (taking into account freight) respectively.

c) The iron pad is provided with a T-bolt insertion seat and a rail shoulder, and the elastic strip is tightened by tightening the nut of the T-bolt. The elastic clips designed in matching have a larger range than the existing elastic clips in my country (all kinds of elastic clips have a range of 14 mm), high fatigue strength, and small buckle pressure attenuation of the elastic clips when using a lower stiffness rail elastic pad.

d) An insulating block is provided between the rail shoulder and the rail on the iron pad to improve the insulation performance of the fastener system.

e) An insulating buffer pad is provided between the iron pad and the concrete sleeper or track plate to buffer the impact of the train load on the concrete sleeper or track plate, while improving the insulation performance of the system. The insulating buffer pad is provided with ribs around it and a drainage port is left, which can effectively improve the water film resistance.

f) The same iron pad can be installed with a variety of elastic clips (conventional buckle pressure elastic clips and small buckle pressure elastic clips), and different line resistances can be obtained by using rail pads with different friction coefficients (rubber pads or composite pads). It can be used in sections requiring large resistance and sections requiring small resistance, meeting the requirements for laying seamless lines under various line conditions.

g) The iron pad is fastened with the insulating sleeve pre-buried in the concrete sleeper or track plate through anchor bolts. The embedded sleeve is provided with a spiral reinforcement positioning hole to facilitate accurate positioning of the spiral reinforcement. The embedded sleeves in the concrete sleeper or track slab are arranged symmetrically, which is convenient for the reinforcement design of the concrete sleeper or track slab.

h) No spare parts are required when adjusting the track direction and track gauge. It is achieved by moving the iron pad with oblong holes. It is a continuous stepless adjustment. The track direction and track gauge can be set and the operation is simple and convenient.

i) The height adjustment of the rail is large, which meets the use requirements of ballastless track. The filling pad under the rail can achieve stepless adjustment of the height.

j) This fastener does not require special spare parts when installed at the rail joint, and does not hinder the installation of the joint clamp.

In view of the key technical problems that the fastener system of the ballastless track of the passenger dedicated line needs to solve, such as high elasticity, high insulation, strong structural versatility, small pressure attenuation of the spring clip and high fatigue strength, reliable connection with the foundation, and large adjustment of the height and left and right positions of the rails, the following optimization improvements have been made in the research of this fastener system:

1) Improve the versatility of the fastener structure;
2) Improve the insulation performance of the fastener system;
3) Reduce the pressure attenuation of the spring clip and improve its fatigue strength;
4) Improve the reliability of the connection between the fastener system and the foundation;
5) Reduce the stiffness of the fastener system;
6 ) Improve the reliability of T-bolt fixation in the iron pad

Step 1: Place the rail pad:
Clean the mud on the rail-bearing surface of the iron pad, and place the rail pad on the rail-bearing surface of the iron pad in the correct direction.

Step 2: Place the rail
Clean the mud on the upper and lower surfaces of the rail bottom, and place the rail in the middle of the rail pad.

Step 3: Place the insulation block
Place the No. 9 insulation block between the rail and the iron pad shoulder. Do not knock it violently to make it fit. The contact surface between the insulation block and the rail should be close. If the gap between the insulating block and the shoulder of the iron pad is greater than 1mm, it should be replaced with a No. 10 insulating block.

Step 4: Place the T-bolt
Apply oil to the threaded part of the T-bolt and then place it.

Step 5: Place the spring bar
Place the two supporting points at the rear end of the spring bar in the grooves on the two supporting platforms of the iron pad, and buckle the insulating block at the front end.

Step 6: Place the flat washer and nut to tighten the spring bar
Place the flat washer and nut, lift the T-bolt, tighten the nut by hand (the nut and the bolt should be aligned, and do not tighten it obliquely), confirm that the bolt is vertical, and then tighten the nut with a torque-controlled wrench or machine to install the spring bar in place.

Step 7: Tighten the anchor bolt
After confirming that the track gauge and track direction are appropriate, use a torque-controlled wrench or machine to tighten the anchor bolt with a torque of 300~-350 Nm.