Rail transit, as a core pillar of modern transport, ensures efficient and safe operations. Track system stability and reliability directly affect performance. Composed of rails, sleepers, fasteners, pads, and foundations, rubber pads—though small—play an irreplaceable role in load transfer, environmental adaptation, and maintenance. Made from natural or synthetic rubber, these elastic components act as a “flexible bridge” between rails and sleepers. Their performance determines track comfort, durability, and environmental standards. This article explores the functions of rail pads in railway systems through their concepts, features, and material technologies.
Overview of Railway Track Pads
Railway under-rail rubber pads are critical components installed between steel rails and concrete sleepers. Their primary functions include cushioning high-speed vibrations and impacts generated by passing vehicles, protecting the subgrade and sleepers, and providing electrical insulation for signaling systems. Additionally, as these pads are exposed to outdoor conditions, they must exhibit excellent resistance to natural aging, extreme temperatures, and environmental stressors. For subway applications, rubber pads must also deliver superior vibration damping and noise reduction.
Key Features of Railway Under-Rail Rubber Pads
1.Shock Absorption, Aging Resistance, Wear Resistance, Stability, and Temperature Tolerance:
Composed of materials such as natural rubber, styrene-butadiene rubber (SBR), chloroprene rubber (CR), HDPE blends, EVA blends, and high-density polyethylene (HDPE), these pads offer high elasticity and maintain structural integrity across varying temperatures without deformation or fracture.
2.Long Service Life and Low Maintenance Costs:
Extended lifespan with minimal replacement and repair expenses.
3.Comprehensive Compatibility:
Available in various models suitable for 43 kg, 50 kg, and 60 kg rail types, as well as wooden and concrete sleepers.
Core Performance Advantages
1.Mechanical and Environmental Adaptability:
·Force-adaptive deformation capability, exceptional vibration damping, minimal compression deformation, high elasticity, and resistance to aging and wear. Designed with a closed-cell structure to prevent mud infiltration.
·Excellent electrical insulation meets signaling system requirements.
2.Durability and Ease of Maintenance:
Lifespan exceeds traditional materials (e.g., cement crossing plates) by over threefold. Laboratory tests confirm resistance to permanent deformation under pressures exceeding 80 tons. Simplified installation reduces maintenance costs.
Engineering Application Value
1.Enhanced Safety and Operational Efficiency:
·Mitigates vehicle stalling and accidents caused by uneven surfaces at railway crossings, improving traffic flow.
· Replaces outdated materials like asphalt, stone slabs, and steel plates, resolving unevenness and frequent maintenance issues to enhance track smoothness.
2.Noise Reduction and Comfort:
Eliminates impact noise during vehicle passage, reduces wheel-rail noise, and improves environmental quality near crossings.
Analysis of Material Technologies for Railway Rubber Pads
1.Styrene Butadiene Rubber (SBR) Pads — Cost-Effective Solution
SBR exhibits physical properties and processing performance similar to natural rubber, with superior wear resistance, heat resistance, aging resistance, and vulcanization speed.
Material Characteristics:
·Outstanding wear resistance and aging resistance; high tensile strength suitable for conventional railways and urban transit.
·Dynamic elasticity from styrene-butadiene copolymer structure effectively absorbs 20–50 Hz mid-low frequency vibrations, reducing stress concentration between rails and sleepers.
2.Nitrile Rubber (NBR) Pads — Heavy-Duty and Oil-Resistant Applications
NBR, synthesized via emulsion polymerization of butadiene and acrylonitrile, offers high wear resistance, heat resistance, and adhesion. Limitations include poor low-temperature performance, ozone resistance, and electrical properties.
Material Characteristics:
·Exceptional resistance to mineral oils, ideal for freight yards and port railways with frequent oil exposure.
·High damping and resistance to compression set, capable of withstanding repeated loads from axles exceeding 25 tons.
3.Ethylene-Vinyl Acetate (EVA) Pads — Lightweight Noise Reduction
·Low density, flexibility, and inherent electrical insulation make EVA ideal for weight-sensitive applications like subway floating slab tracks and high-frequency vibration scenarios.
·Closed-cell structure (water absorption <1%) combined with hydrophobic coatings prevents mold growth in humid tunnel environments (microbial count ≤50 CFU/cm²).
Conclusion
Though under-rail rubber pads are “small components” in track systems, they bear a “significant mission” to enhance transportation quality and ensure safe operations. Glory Rail, as an expert in track systems and a provider of integrated solutions, delivers tailored elastic support products for all scenarios.
We are committed to supplying high-performance under-rail products that elevate the safety, durability, and sustainability of rail transit systems.