The WJ-7 railway fastener system is a key component designed for ballastless track without shoulder, designed to meet the stringent technical standards for fastener systems on passenger dedicated lines. It is widely used in embedded sleepers (double-block sleepers and long sleepers) and slab ballastless tracks on bridges, in tunnels and on roadbeds.
System composition
The WJ-7 fastener is composed of a variety of components. T-bolts, nuts and flat washers work together to apply fastening pressure to the spring clips. The spring clips are divided into W1 type with a diameter of 14mm and X2 type with a diameter of 13mm. W1 type spring clips are used in general sections, and X2 type is used in sections with low resistance. The insulating block is set between the spring clip and the rail to ensure that the fastener has good insulation performance.
The rail pad is laid under the rail, which is divided into A and B according to the railway operation requirements. Category A is used for high-speed railways that also take freight into account, with a thickness of 12mm; Category B is used for high-speed railways that only run passenger cars, with a thickness of 14mm. Each category is further subdivided into ordinary rubber pads and composite pads with small resistance fasteners.
The iron pad plays a key role in force transmission, with a thickness of about 26 mm. The vertical, lateral and longitudinal forces generated by the train operation are transmitted to the iron pad through elastic bars, rubber pads under the rail or height adjustment pads. The insulating buffer pads and height adjustment pads below transmit the vertical force to the lower ballastless track. The longitudinal and lateral forces are transmitted through the anchor bolts connected to the iron pad and tightened in the embedded sleeve. The embedded sleeve is made of nylon material and is embedded in the specified position when the track plate is manufactured. In addition, there are heavy-duty spring washers, flat washers and other components to ensure the stability of the system.
Functional characteristics
The WJ-7 system has excellent height and gauge adjustment capabilities. In terms of height adjustment, the maximum adjustment amount can reach 30mm by replacing height adjustment pads of different thicknesses under the rail and under the iron pad. The gauge adjustment relies on the oblong hole at the connection between the iron pad and the spiral spike, allowing the iron pad to move left and right, and the adjustment amount is ±10mm. In terms of force performance, when using W1-type spring bars and rubber pads, the longitudinal resistance of each set of fastener rails is not less than 9kN; under the small resistance configuration (X2-type spring bars and composite pads), it is 4.0kN±1.0kN. In terms of assembly buckle pressure, it is not less than 18kN under W1-type spring bars and not less than 6kN under X2-type spring bars. After 3×10⁶ load cycle fatigue tests, the performance of each component is stable, the gauge expansion and the change rate of various mechanical properties are within the specified range, and the insulation resistance is not less than 5kΩ.
The WJ-7 railway fastener system, with its precise structure and excellent performance, lays a solid foundation for the safe and stable operation of high-speed railway ballastless tracks and is an indispensable part of modern railway track structures.