What is the hardness of the railroad pad?

Rail pads are elastic polyurethane mats which are interposed between steel rails and railway sleepers to protect the sleeper top from wearing and impacting.

 

The starting stiffness of a rail pad is designed to not be high so that their relative deformation under the spring clip toe loads is greatly substantial. In this way, it can guarantees the rail pad maintaining in close contact with the rail despite of any vertical movements of the latter. In addition, the reason why rail pads made up of rubber or plastic is to dampen the shocks of vibration of a passing train.

 

What is the hardness of the railroad pad?

 

Rail pad hardness varies by material (Rubber, EVA, HDPE) and application, measured by Shore Hardness (A/D) or stiffness (kN/mm), but generally ranges from around 72-80 Shore A for rubber pads, while HDPE/EVA pads can be much harder, up to ≥98A, with stiffness classifications distinguishing soft (<80 kN/mm) from hard (>150 kN/mm) pads for specific track dynamics.

 

 

Hardness by Material Type

 

• Rubber Pads: Often specified in Shore Hardness (e.g., 72-80 Shore A) or stiffness (e.g., 90-130 kN/mm for some), providing significant vibration damping and flexibility.

 

• HDPE (High-Density Polyethylene) Pads: Known for high hardness, often listed as ≥98A, providing stiffness for heavy-haul or high-speed tracks.

 

• EVA (Ethylene Vinyl Acetate) Pads: A blend that offers a balance, with hardness typically around 90-92A, balancing elasticity and load support.

 

 

HDPE Rail Pad
Technical Parameter	Unit	Technical Requirement	Value
Density	g/cm3	0.95-0.98	0.95
Tensile Strength	Mpa	≥19	19
Elongation	%	>80	150
Melting Point	℃	170-190	190
Insulation Resistance	Ω	≥1×1010	3.5 ×1010
Hardness	A	≥98	98(A)

 

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

 

EVA: Polyethylene 80%, Vinyl Acetate 20%.
Technical Parameter	Unit	Technical Requirement	Value
Density	g/cm3	0.95-0.98	0.95
Tensile Strength	Mpa	≥15	16
Elongation	%	>500	550
Melting Point	℃	170-190	170
Insulation Resistance	Ω	≥1×1010	5.0 ×1010
Hardness	A	≥90	92(A)

 

Is using railway pads with lower hardness more beneficial for railway operational safety?

 

Yes, softer railway pads are often more beneficial for operational safety, especially in urban/noisy areas, as they significantly reduce vibrations and noise, improve ride comfort, and protect tracks from wear, leading to fewer failures; however, harder pads might suit heavy freight for stiffness, but softer pads offer better damping, reducing stress on components and enhancing overall track longevity and safety by absorbing impacts.

 

 

When Harder Pads Might Be Used

 

• Heavy Freight: Harder pads can provide the necessary stiffness for heavy cargo routes, though softer, thicker pads often handle impacts better.

 

• Specific Track Conditions: Some flat concrete tracks might use stiffer (harder) pads, while rocky or high-speed tracks often benefit from thicker, softer pads.

 

GNEE's 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.

 

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