Selection and Performance Matching Technology of Elastic Rail Fasteners
What are the common types of elastic rail clip fasteners and their adaptive scenarios?
The WJ-8A type fastener adopts A-class elastic base plate with a static stiffness of 35±5kN/mm, suitable for passenger dedicated lines that take into account freight transportation and have a maximum speed of 250km/h. The WJ-8B type fastener is matched with a B-class elastic base plate with a static stiffness of 23±3kN/mm, suitable for ballastless tracks with double-block sleepers and passenger dedicated lines with a maximum speed of 350km/h. The WJ-8C type fastener also uses a B-class elastic base plate, adapting to CRTSII type track slabs and meeting the requirements of 350km/h high-speed operation. Ordinary elastic rail clips are suitable for conventional railways and special lines of factories and mines, providing basic clamping force. Special elastic rail clips for heavy-haul lines are made of high-strength materials with greater clamping force, which can resist repeated impacts of heavy-haul trains.
What are the core performance indicators of elastic rail clips? How to guarantee them?
The core performance indicators of elastic rail clips include clamping force, elasticity, fatigue life and corrosion resistance. The clamping force must meet the design requirements. The clamping force of elastic rail clips for ordinary lines is not less than 10kN to ensure that the rail does not move. The elasticity index determines the shock absorption effect, which must be matched with the stiffness of the rail pad to avoid resonance. The fatigue life requires no cracks after millions of cycles of tests to ensure long-term use stability. Corrosion resistance is achieved through surface treatments such as galvanizing, adapting to corrosive environments such as humidity and coastal areas. Guarantee measures include selecting high-quality spring steel materials, strictly controlling the heat treatment process, and conducting piece-by-piece performance testing before leaving the factory.
What are the requirements for the stiffness matching between elastic rail clip fasteners and rail pads?
The stiffness of elastic rail clip fasteners and rail pads must be designed collaboratively to avoid excessive track vibration or insufficient clamping force caused by mismatched stiffness. In high-speed lines, the elasticity of elastic rail clips must be matched with low-stiffness rail pads. The WJ-8B type elastic rail clip is matched with a B-class pad with 23±3kN/mm to achieve good shock absorption effect. Heavy-haul lines need to improve system stiffness, increase the clamping force of elastic rail clips, and match them with high-stiffness pads to prevent rail displacement. Conventional railways can adopt a medium stiffness combination to balance shock absorption effect and installation cost. Stiffness matching must be determined through line dynamics calculations to ensure that wheel-rail forces are within a reasonable range and extend the service life of components.
What are the key points of performance testing for elastic rail clips after installation?
After installation, it is necessary to test the clamping force of the elastic rail clip with a special testing tool to ensure that it is not lower than the design value, ≥10kN for ordinary lines, and higher for high-speed lines. Check the fit between the elastic rail clip, rail and iron base plate, with a gap ≤0.5mm to avoid uneven force. Visually inspect the elastic rail clip for deformation, cracks and other defects to ensure no damage during installation. Conduct vibration tests to verify the elastic recovery ability of the elastic rail clip under simulated train loads without permanent deformation. Conduct regular follow-up tests, once every six months for high-speed lines and once a year for conventional lines, and replace aging or failed elastic rail clips in a timely manner.
What are the performance guarantee measures for elastic rail clips under extreme working conditions?
In high-temperature environments, elastic rail clips should be made of heat-resistant spring steel to avoid elastic degradation caused by high temperature, and the surface should be coated with a high-temperature resistant anti-corrosion coating. In low-temperature environments, elastic rail clips with good low-temperature toughness are preferred, which have passed low-temperature impact tests to ensure no brittle fracture below -40℃. Under heavy-load working conditions, elastic rail clips adopt a strengthened heat treatment process to improve yield strength and tensile strength, increasing the clamping force reserve. In coastal humid environments, elastic rail clips are treated with hot-dip galvanizing + passivation to improve salt spray corrosion resistance. Guarantee measures also include optimizing the structural design of elastic rail clips to reduce stress concentration and extend fatigue life.