Description of W21 Rail Fastening System
The W21 fastening system is a highly advanced elastic rail fastening solution. First and foremost, it’s mainly designed for ballast tracks in various rail applications, including high-speed railways, urban transit systems like metros and light rail, and heavy-haul railways.
Renowned for its high elasticity, stability, and ease of maintenance, the system has been widely adopted globally. To provide a comprehensive view, the following sections will detail its components, functional features, and application scenarios, showing how it meets modern rail infrastructure demands.
System Composition and Key Components
The W21 system comprises multiple critical components that work together to ensure track stability and reliability:
Skl21 Elastic Rail Clip
Made from 60Si2CrA or 38Si7 spring steel, with a diameter of 13mm. Surface treatments include oil coating, spray painting, etc.
Fatigue life exceeds 5 million cycles under a spring deflection of 9.1mm and swing deflection of 1.42mm. Minimum clamping force is theoretically ≥9kN, providing strong rail-locking capability.
Ss35 Screw Spike
Sizes: M24×150mm, M24×160mm, etc. Materials vary by grade: Q235 (Grade 4.6), 35# steel (Grade 5.6), 45# steel (Grade 8.8). Surface treatments include oil coating, blackening, galvanization, etc.
Plastic Dowel
Made of HDPE (high-density polyethylene) or reinforced PA66 (nylon 66), compatible with different helical spike sizes. Inserted into concrete sleepers for stable support.
Guide Plate & Under-Rail Pad
Guide Plate: Suitable for UIC54, UIC60, 50kg/m, 60kg/m rails, made of reinforced PA66 with color-coded designs.
Under-Rail Pad: Made of EVA or rubber, compatible with UIC54/UIC60 rails, providing elastic buffering, insulation, and vibration reduction.
Advantages of the W21 Fastening System
High Elasticity and Vibration Damping
The Skl21 clip, combined with a high-elastic under-rail pad, effectively buffers train loads, reducing wear and deformation of track components. Specifically, the static stiffness of the pad ranges from 30–40kN/mm for conventional lines, while it decreases to 20–30kN/mm for high-speed lines.
Reliable Clamping Force and Insulation
Clamping force ≥9kN ensures secure rail-sleeper connection, preventing longitudinal/transverse rail movement. Additionally, insulation resistance >5kΩ avoids current leakage in track circuits, ensuring signal system stability.
Flexible Gauge Adjustment
Gauge adjustment range of ±10mm is achieved via continuous stepless adjustment using slotted guide plates, requiring no additional parts for easy on-site adaptation.
Wide Applicability
Suitable for trains with axle loads ≤260kN, covering high-speed (≥250km/h), conventional (≤250km/h), and heavy-haul lines. Compatible with ballasted/ballastless tracks, bridges, tunnels, and other complex environments.
Long Service Life and Low Maintenance
Designed for a 10–15-year lifespan. Components can be pre-assembled in factories to reduce on-site installation time. Universal parts minimize maintenance efforts and operational costs.
Technical Specifications of W21 Rail Fastening System
|
Component |
||||
|
Component |
Qty For One Sleeper |
Material |
Size |
Remark |
|
4 |
60Si2MnA, 60Si2CrA, 38Si7 |
SKL 21 |
Hardness:42-47HRC 5 million cycles without breaking Standard: DIN17221, GB/T1222 |
|
|
4 |
Grade 4.6: Q235; Grade 5.6: 35# |
Ss35,DHS35, etc |
Standard: ISO898-1, UIC864-1, NF F500-50 |
|
|
4 |
HDPE, Reinforced Nylon 66 (PA66) |
SDU 25, etc |
To insert into a concrete sleeper |
|
|
4 |
Reinforced Nylon 66 (PA66) |
Wfp 21K-12, etc |
Depends on rail size and fastener system model |
|
|
2 |
EVA, TPU, or rubber |
Zw 139/160/7, etc. |
Depends on rail size and fastener system model |
|
Advantages
How to Find a Qualified Rail Fastener Manufacturer?
Please choose LTRF.
Why Choose LTRF?
- Strong Technical Expertise
LTRF boasts a dedicated R&D center. Moreover, it maintains long-term collaborations with major industry players such as China Railway, CRCC, and the Academy of Railway Sciences. In addition, it also partners with leading railway universities. As a result, LTRF has been able to develop various innovative fastening systems for both domestic and international markets. Notably, all these systems possess independent intellectual property rights. Indeed, to date, LTRF holds over 30 invention and utility model patents.
- Professional Manufacturing
LTRF always aims for the best. We carefully choose the materials we use and make sure every part is made with great care and skill. And we believe in doing things perfectly, so we keep coming up with new ideas and check the quality of our products very carefully to make sure they’re good.
We work fast to make sure you get your order on time. And we offer good service before and after you buy something. At LTRF, we also focus on what our customers need. We’re committed to making good products and providing great service in everything we do.
- Competitive Pricing + Superior Quality
LTRF control the cost of each process, and the finance department updates the cost calculation regularly.
Furthermore, LTRF’s advanced testing equipment endows the company with comprehensive quality inspection capabilities for the entire fastener system. This meticulous quality-control measure is crucial for ensuring product reliability. Importantly, LTRF holds ISO and CRCC certification for railway products. These certifications not only demonstrate the company’s compliance with international and industry-specific standards but also enhance its credibility in the market.
