WJ-8 Fastening System

WJ-8 fastener is a kind of non-open shoulder stopper fastener used on ballastless track of high-speed rail in China. It is composed of spiral spike, flat washer, spring bar, insulated gauge block, gauge baffle, underrail cushion plate, iron cushion plate, elastic cushion plate under iron cushion plate and embedded casing, etc. In addition, it also includes underrail fine adjustment plate and iron cushion plate down high cushion plate to meet the needs of high and low adjustment.

Component Composition and Description

The WJ-8 fastening system (hereinafter referred to as the fastening system) consists of a screw spike, flat washer, clip, insulating block, gauge stop, rail base plate, steel base plate, elastic pad beneath the steel base plate, and embedded sleeve. Additionally, to accommodate rail height adjustment, it includes a micro-adjustment base plate beneath the rail and a height-adjustment pad beneath the steel base plate.

1. Clip

Clips are available in two types: the W1 type for general track sections and the X2 type for potential use on bridges. The diameter of the W1 clip is 14 mm, while that of the X2 clip is 13 mm.

2. Rail Base Plate

Rail base plates are available in two types: rubber base plates for general track sections and composite base plates for potential use on bridges.

3. When reducing track resistance is required on bridges, X2 clips paired with composite pads may be used. In this case, the longitudinal resistance of each fastening unit is 4 kN.

4. Gauge Blocks

Gauge blocks are divided into WJ8 gauge blocks for general sections and WJ8 joint gauge blocks for rail joints.

WJ8 gauge plates for general sections come in eleven specifications: No. 2, No. 3, No. 4, No. 5, No. 6, No. 7, No. 8, No. 9, No. 10, No. 11, and No. 12. The No. 7 gauge plate is used for standard gauge. Among these, the No. 10, No. 11, and No. 12 specifications can be used at rail joints.

WJ8 joint gauge plates are available in eight sizes: No. 2, No. 3, No. 4, No. 5, No. 6, No. 7, No. 8, and No. 9. Size No. 7 is used for standard gauge.

5. Insulating Blocks

Insulating blocks are classified into Type I and Type II. Type I is used in general sections, while Type II is used at rail joints.

6. Elastic Pad Under Rail Base Plate

Elastic pads under rail base plates are categorized into Type A and Type B. Type A is used for passenger-dedicated lines also serving freight; Type B is used for passenger-dedicated lines.

7. Screw Spikes

Screw spikes are available in S2 and S3 types. S2 type is used when rail adjustment height does not exceed 15mm; S3 type is used when exceeding 15mm.

8. Pre-embedded Sleeve

This component is pre-installed in the sleeper or track slab. Installation accuracy must meet the requirements of Figure 2, and the top surface of the pre-embedded sleeve shall be flush with the rail-bearing surface of the sleeper or track slab. After installation, the pre-embedded sleeve shall be covered with a plastic (or other material) cap to prevent rainwater and mud ingress.

9. Height-Adjusting Shims

Height-adjusting shims comprise two types: under-rail fine-adjustment shims and under-iron-plate height-adjusting shims. They are placed between the under-rail shim and iron plate, and between the elastic shim under the iron plate and the rail-bearing surface of the sleeper or slab track, respectively. Under-rail fine-adjustment shims are available in four thicknesses: 1mm, 2mm, 5mm, and 8mm. Under-iron-plate height-adjustment shims come in two thicknesses: 10mm and 20mm. These height-adjustment shims consist of two plates and must be used in pairs.