What is the difference between under-rail rubber pads and Under- ballast Rail Pads?
In the architecture of a vibration-free railway track, elasticity is applied at multiple levels. A frequent point of confusion for procurement teams arises between the Under-Rail Rubber Pad and the Under-Ballast Pad (industry-standard term: Under Ballast Mat or UBM). While both are technically "elastic pads," they operate on completely different scales and serve distinct engineering purposes. Understanding this distinction is vital for accurate project specification.
1. Scale and Location: The Micro vs. The Macro
The primary difference lies in their physical application.
The Rail Rubber Pad is a component of the fastening system. It is a small, discrete pad (roughly the size of a hand) installed directly between the steel rail foot and the concrete sleeper. It is a "point" solution, installed at every sleeper.
| 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 |
In contrast, the Under Ballast Mat (UBM) represents a "surface" solution. It is a continuous elastic layer-often supplied in large rolls or mats-installed underneath the entire ballast bed, sitting directly on top of the subgrade, bridge deck, or tunnel floor. Think of the rail pad as a cushion for the rail, while the ballast mat acts as a giant carpet for the entire track superstructure.
2. Functional Dynamics: High-Frequency vs. Structural Isolation
Functionally, they address different vibration spectrums.
The Rail Elastic Pad serves as the first line of defense. Its job is to dampen high-frequency dynamic impact generated at the wheel-rail interface, protecting the sleeper from cracking and providing electrical insulation.
The Under-Ballast Pad, however, functions as a structural isolator. It is designed to dampen low-frequency vibrations that travel through the ground (structure-borne noise). This makes UBMs essential for tracks running over bridges (to protect the bridge deck from ballast abrasion) or through urban tunnels (to prevent shaking in nearby buildings).
GNEE RAILWAY RAILWAY: Comprehensive Vibration Solutions
At GNEE RAILWAY RAILWAY, we understand that effective noise and vibration control often requires a multi-layered approach. We manufacture and supply the full spectrum of elastic components.
GNEE RAILWAY RAILWAY is equipped with rail pad production lines for 130sets of machines, for the whole process of injection, refining rubber, sulfuration, moulding and inspection, etc. We own the most engineers for rail pad development, design, production and inspection, with annual production capacity reaching up to 2000, 000 pieces. What's more, rail pads for high speed rail lines are our featured products, including both the elastic rubber plates and height adjustment pads.