The rail pad, also known as bottom plate, is an elastic polyurethane pad assembled between the rails and sleeper to protect the top of the sleeper from wear and impact. The initial stiffness of the rail pad is not so high that the deformation of the rails under the load of the spring is very large. This mechanism ensures that the rail pad moves as close as possible to realize close contact with the track.
Which type of railway pad material is the most durable?
For maximum durability in harsh conditions, polyurethane (PU) railway pads generally surpass traditional rubber, offering superior resistance to extreme temperatures, chemicals, and wear, often lasting 1.5-2 times longer, though high-density EPDM rubber and composite pads (like fiber-reinforced PU) also provide excellent strength, wear resistance, and specialized performance for heavy-haul or turnout areas.
Top Contenders for Durability of railway pad:
- Polyurethane (PU): Engineered for extreme environments, PU excels in heavy-haul lines, tunnels, and bridges due to its outstanding resistance to chemicals, moisture, UV, and temperature fluctuations, with better abrasion/tear resistance than rubber.
- Composite Pads: These combine materials, like fiberglass-reinforced PU, to significantly boost wear resistance (up to 40%) in high-stress areas like switch points, or rubber-metal hybrids for added structural integrity.
- High-Density EPDM Rubber: EPDM (Ethylene Propylene Diene Monomer) offers excellent weathering and aging resistance, making it very tough for moderate to extreme climates, outperforming natural rubber in harsh sun and cold.
Why Rubber Rail Pad is Popular (But Has Limitations)?
- Natural Rubber: Very resilient and cheap, it's a long-standing standard for vibration damping but can degrade faster under extreme heat or chemicals.
| Rubber Rail Pad | ||
| Technical Parameter | Unit | Value |
| Stiffness | KN | 90-130 |
| Hardness Shore A | ℃ | 72-80 degree |
| Electronic Resistance | Ω | ≥ 106 |
| Tensile Strength before Aging | Mpa | ≥12.5 |
| Elongation before Aging | % | ≥250 |
- SBR (Styrene-Butadiene Rubber): Offers better aging resistance than natural rubber, used in many conventional systems, but still less durable in extreme conditions than PU.
Rail pads Functions
Rail pads plays 2 main parts in railway system. It can diminish shock and impact on steel rail, as well as reduce resonant vibration aroused from the concrete sleepers (lowest resonant frequency about 200Hz), and absorb the vibration deviation (about 0.12mm amplitude, 1000Hz) of the track part between sleepers. What's more, rail pads can prevent abrasion and crushing of the sleeper under the foot of the track.
The rubber rail pads are usually designed to have a specific load-deflection characteristic. The initial stiffness of the pads is designed to be very low, making their deformation under the spring toe load quite large. This ensures that despite any vertical movement of the rail, the pad is still in close contact with it. When the wheel is above the pad, the stiffness of the track must be high to prevent large movement, resulting in loose metal spring washers. This load deflection characteristic can be obtained by introducing grooves in the rubber pad.
Our EVA/HDPE/rubber rail pads are with high elasticity, applying to types for rails such as rail UIC54, UIC60, BS80lbs,BS100lbs, and sizes as ordered. The pads can be customized with or without grooves, in various possible designs, depending on customers' requirements.