Rail Pad Material Classification and Application Technology
What are the core performance differences between rail pads of different materials?
Rubber pads are mainly made of natural rubber or synthetic rubber, with low cost and good elasticity, which can effectively absorb vibration and are widely used in conventional railways and urban rail transit. Polyurethane pads have both high elasticity and high strength, and their wear resistance is more than 30% higher than that of rubber pads, suitable for high-frequency and heavy-load scenarios such as heavy-haul railways and high-speed railways. EVA pads are made of ethylene-vinyl acetate copolymer, with excellent elasticity, flexibility and insulation. Their insulation resistance can reach ≥1×10¹⁰Ω, suitable for urban rail transit, bridges and tunnels and other areas with high requirements for shock absorption and insulation. Composite pads combine the advantages of various materials such as rubber, plastic and fiber. The rubber layer provides elastic buffer, and the fiber reinforcement layer improves the bearing capacity, adapting to special areas such as bridges and tunnels. The performance differences of pads of different materials determine their applicable line conditions.
What is the corresponding relationship between the functional classification of rail pads and application scenarios?
Ordinary shock-absorbing pads focus on the basic shock absorption function, with a static stiffness of 20-60kN/mm, suitable for lines with general requirements for noise and vibration control such as internal railways of factories and mines. Insulating pads add insulating materials such as glass fiber and epoxy resin, with an insulation resistance of ≥10⁹Ω, used in track circuit areas to prevent current leakage from interfering with signal transmission. Height adjustment pads have various thickness specifications from 1-30mm, mostly made of polyethylene or nylon, used to adjust the height of rails during track construction and maintenance, and can be superimposed with ordinary pads to achieve precise leveling. Continuous rubber pads have grooves on the surface, which can ensure close contact with the rail base and reduce wear, widely used in industrial scenarios such as ports and shipyards. Discontinuous rubber pads are structurally adapted to specific force requirements and perform stably in heavy-load industrial lines such as steel plants and cement plants.
What are the advantages of the structural design of composite rail pads?
THRAIL elastic composite pad adopts a structure of two layers of rubber with a 0.5-0.7mm high-quality steel plate embedded in the middle, which is formed by hot glue compounding, with a reasonable structure and high lateral stiffness. The cross-section of the pad is slightly convex in the middle, so the force is more uniform. The small rectangular convex strips on the surface are easy to deform, which not only facilitates contact with the track, but also enhances elasticity and shock absorption effect. The rectangular grooves are arranged along the cross-sectional direction of the pad to reduce the overall lateral deformation after stress and reduce the damage to the rubber surface caused by extrusion. The width of the steel plate is in a specific proportion to the width of the pad, which not only enhances the stiffness but also facilitates curling and transportation, with a temperature application range of -20℃-80℃. It still performs well after 2 million fatigue performance tests, and is not easy to be damaged even after long-term use, adapting to high-frequency and heavy-load scenarios.
What are the key technical requirements for the installation and use of rail pads?
The width of the composite pad is 4-5mm smaller than the width of the rail base. After installation, through the pre-compression force of the track pressing plate, it can be in close contact with the rail base and the supporting surface to make up for the unevenness of the supporting surface. Before installation, it is necessary to check the elasticity and integrity of the pad. Rubber pads should avoid direct sunlight and high-temperature storage to prevent aging and failure. When installing insulating pads, it is necessary to ensure that they match the hole positions of the insulating sleeves to avoid affecting the insulation effect. The insulation resistance under wet conditions should not be less than 5kΩ. During installation, it is necessary to clean up foreign objects under the pad, such as gravel and gasket residues, to prevent the rail base slope from shifting. During use, it is necessary to regularly check the wear and deformation of the pad, and replace it in time if aging or damage is found to ensure shock absorption and stability performance.
How to select suitable rail pads in extreme environments?
In high-temperature environments, high-temperature resistant rubber pads or composite pads with heat-resistant components should be selected to avoid softening and deformation caused by high temperature. In low-temperature environments, low-temperature resistant rubber or polyurethane pads should be preferred to ensure good elasticity below -25℃ without brittle fracture. Humid and coastal environments should adopt anti-corrosion composite pads or ceramic pads to resist rust and erosion. Desert environments require pads with good sealing and wear resistance, matching the fastening system with strong dust-proof performance. For industrial sites with oil pollution, oil-resistant rubber pads should be selected to avoid performance degradation caused by oil erosion.