Product Description
WJ-8 rail fastening system (also known as WJ-8 elastic fastener) is suitable for rails with a gauge of 1435 mm and a speed of 60 kg/m.
(1) Fastener composition
●WJ-8 fasteners are composed of spiral spikes, flat washers, spring bars, insulating gauge blocks, gauge baffles, rail pads, iron pads, elastic pads under the iron pads, and embedded sleeves. To meet the needs of height adjustment, they also include rail fine-tuning pads and iron pad height adjustment pads.
●There are two types of spring bars, namely W1 spring bars (diameter 14 mm) and X2 spring bars (diameter 13 mm). X2 spring bars are used when small resistance fasteners are used on bridges.
●There are two types of gauge baffles, namely gauge baffles for general sections and joint gauge baffles for clamping plates.
●Elastic pads under iron pads are divided into two types, A and B (both with a thickness of 12 mm). Class A elastic pads are used for high-speed railways that also take freight into consideration, and Class B elastic pads are used for high-speed railways that only run passenger cars.
●Spiral spikes are divided into two types: s2 and s3. When the fastener is installed in a normal state or the rail height adjustment is not greater than 15mm, the s2 type spiral spike is used, and when the height adjustment is greater than 15mm, the s3 type spiral spike is used.
●Two types of rail pads:
① WJ-8A type fasteners use Class A elastic pads (static stiffness of 35±5kN/mm), which are suitable for passenger dedicated line operation conditions with a maximum speed of 250km/h for both freight and cargo;
② WJ-8B type fasteners use Class B elastic pads (static stiffness of 23±3kN/mm), which are suitable for laying double-block ballastless tracks with a maximum speed of 350km/h for passenger dedicated lines;
③ WJ-8C type fasteners use Class B elastic pads (static stiffness of 23±3kN/mm), which are suitable for laying CRTS II type track plates with a maximum speed of 350km/h for passenger dedicated lines.
(2) Main technical requirements
① A certain amount of protective grease should be ensured in the embedded casing, and the grease performance should comply with relevant regulations.
② Joint gauge baffles and insulating gauge blocks should be used at the clamping plate.
③ Spring bar installation standard: The front end lower jaw of the middle part of the spring bar should not contact the insulating gauge block, and the gap between the two should not be greater than 0.5mm or when using a torque wrench to detect the torque of the spiral spike, the Wl type spring bar is 130~170N·m, and the X2 type spring bar is 90~120N·m.
④ Spring bar maintenance standard: The front end lower jaw of the middle part of the spring bar should not contact the insulating gauge block, and the gap between the two should not be greater than 1mm; or when using a torque wrench to detect the torque of the spiral spike, the W1 type spring bar is 130~170N·m, and the X2 type spring bar is 90~120N·m.
⑤ The gauge baffle should be close to the shoulder of the bearing rail groove, and the gap should not be greater than 1mm; the sum of the gaps between the rail and the insulating gauge block, and the insulating gauge block and the iron pad shoulder should not be greater than 1mm.
⑥ Rail left and right position adjustment: ±5mm.
⑦ Height adjustment: 4~+26mm.
Features
The following are the product features and structural characteristics of the WJ-8 fastener system:
Features Of WJ-8 Rail Fastening System
The research and development of this fastener focuses on the following aspects:
- Determine the basic structure of the fastener system to make the structure stable and reasonable;
- Study and solve the problem that both conventional buckling spring rods and small buckling spring rods can be installed on the same structure. The elastic rail clamp meets the technical requirements of the longitudinal resistance of seamless lines laid in roadbeds, tunnels, and bridges;
- Take measures to improve the insulation performance of the fastener system;
- Study technical measures to improve the flexibility of the system and support the development of long-life, high-elastic damping pads and high fatigue strength elastic clips that are compatible with it.
Structural features of the WJ-8 fastening system
The fastener system is a shoulder-free elastic split structure with rail pads. Its structural features are:
- The fastener system is an elastic non-separable fastener with rail pads. Concrete shoulders are provided on concrete sleepers or track slab bearing grooves. The lateral load transmitted from the rails by the train passes through the rail pads and gauge baffles and is finally transmitted to the concrete shoulder, which reduces the position of the lateral load and makes the structure more stable.
- Rail shoulder pads are provided on the rail pads, and insulating blocks made of engineering plastics are provided between the shoulder pads and the rails, which can not only buffer the impact of the rails on the rail pads, but also greatly improve the insulation performance of the fastener system, especially the system. Insulation resistance during rainfall;
- Gauge baffles made of engineering plastics are placed between the rail pads and the concrete shoulder to maintain and adjust the gauge distance while providing insulation;
- A variety of elastic rail clamps (conventional buckle rail clamps and small buckle rail clamps) can be installed on the same rail pad. Different rails (rubber pads or composite pads) with different friction coefficients can be used to obtain different lines. The resistance can be used in areas where high resistance is required or in areas where low resistance is required to meet the requirements of laying seamless lines under various line conditions.
- When assembling the fastener, the front end of the middle leg of the elastic clip contacts the bottom of the rail, avoiding insufficient spring bar pressure or elastic clip stress when the heightening pad is inserted between the rail and the rail pad.
- The spring bar, which is the same as the WJ-7 fastener, has a large elastic stroke and high fatigue strength. When a lower stiffness elastic pad is used, the buckling pressure attenuation of the spring bar is small.
- The rail pad is set under the rail iron pad, the fastener system has good elasticity, and the pad is made of long-life thermoplastic elastomer material.
Comparison
Please see the table below for the differences between WJ-7 and WJ-8 fastener systems.
Comparison of WJ-7 and WJ-8 Rail Fastening System
Serial number | project | Performance |
| | WJ-7 fastener | WJ-8 type fastener |
1 | Adapt to rail type | China 60kg/m rail |
2 | gauge | 1435mm |
3 | Track bottom slope | A 1:40 rail bottom slope is placed on the iron rail pad. | A 1:40 rail bottom slope is placed on the sleeper or track board. |
4 | Rail longitudinal resistance | In general, each group of fasteners is larger than 9kN; for small resistance sections, each group of fasteners is about 4kN. |
5 | System flexibility | The static stiffness of the A-type rail pad is 30~40kN/mm, which is suitable for the 250km/h passenger dedicated line (considering freight transportation); the static stiffness of the B-type rail pad is 20~30kN/mm, which is suitable for the 350km/h passenger line; |
6 | Dynamic and static stiffness ratio | Not more than 2.0. | Not more than 1.5. |
7 | Fatigue performance | The fastener system is tested according to EN 13146-4 when the height is increased by 30mm. After 3 million load cycles, the parts are not damaged, the gauge length is less than 6mm, and the buckle pressure, the longitudinal resistance of the rail and the static stiffness of the rail joint meet the following requirements. : buckle pressure change ≤ 20%; rail longitudinal resistance change ≤ 20%; node static stiffness change ≤ 25%. |
8 | Insulation resistance | The fastener system is tested according to EN13146-5. The insulation resistance between the two rails is greater than 3 Ω·km, and meets the requirements of the track circuit for its insulation resistance. |
9 | Harsh environmental conditions | The fastener system can be successfully disassembled with a manual disassembly tool after the 300h salt spray test described in EN13146-6. |
10 | Rail left and right position adjustment | The adjustment of the left and right position of the single-strand rail: -6 ~ +6mm; gauge adjustment: -12 ~ +12mm, continuous stepless adjustment. | The adjustment of the left and right position of the single-strand rail: -5 to +5 mm; the gauge adjustment: -10 to +10 mm, and the adjustment level is 1 mm. |
11 | Rail height position adjustment | Rail height adjustment position: 30mm; |
12 | Buckle pressure and range | Commonly used elastic rail clips (W1 type): single elastic rail clip buckle pressure is greater than 9kN, and the elastic stroke is 14mm; small resistance elastic rail clip (X2 type): single elastic rail clip buckle pressure is 6kN, and the elastic stroke is 12mm. |
13 | Pull-out resistance of embedded bushings in sleepers | Not less than 100kN. | Not less than 60kN. |
