What are rail pads made of
Release Time:
Oct 20,2022
The currently world-wide used track elastic rail pad materials include: 1.Rubber material: Natural rubber, Styrene-butadiene rubber(SBR), Neoprene, Nitrile rubber, EPDM rubber(Ethylene Propylene Diene Monomer Rubber) 2.Plastic material(HDPE、EVA、Nylon PA 6) 3.TPV- Thermoplastic Elastomer Dynamic Vulcanizate 4.Micro-foamed materials（Micro-foamed TPEE、TPU、TPV） 5.Micro-foamed thermoplastic elastomer 6.Other composite materials After comparison, it is not difficult to find, that there is a major difficulty in obtaining material parameters and properties that are applicable to a wide range of conditions. So we need to choose the proper material for rail pad considering both costs and required performance of the local railway companies.
Why rail pads?
A wide variety of systems is available to reduce the vibration and noise generated by rail transport with most of these systems utilizing resilient elements.
Rail pads are one of easiest and most common solutions to implement to reduce rail vibrations.
What are rail pads made of?
The rail pad, or called rail elastic pad, refers to a pad made of rubber or plastic, which is installed between the rail and the concrete under-rail component. The main function of rail elastic pad is to buffer the high-speed shock and vibration generated when the vehicle passes the rail, protect the roadbed and sleepers, and electrically insulate the railway signal system.
The currently world-wide used track elastic rail pad materials include:
- Rubber material: Natural rubber, Styrene-butadiene rubber(SBR), Neoprene, Nitrile rubber, EPDM rubber(Ethylene Propylene Diene Monomer Rubber)
- Plastic material(HDPE、EVA、Nylon PA 6)
- TPV- Thermoplastic Elastomer Dynamic Vulcanizate
- Micro-foamed materials（Micro-foamed TPEE、TPU、TPV）
- Micro-foamed thermoplastic elastomer
- Other composite materials
Compare of the materials’ performances
Rubber
|
Technical Parameter |
Unit |
Value |
|
Stiffness |
KN |
90-130 |
|
Hardness Shore |
A |
72-80 |
|
Electronic Resistance |
Ω |
≥ 106 |
|
Tensile Strength before Aging |
Mpa |
≥12.5 |
|
Elongation before Aging |
% |
≥250 |
HDPE
|
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 Shore |
A |
≥98 |
98(A) |
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 Shore |
A |
≥90 |
92(A) |
Comparion of EPDE+PP-X / TPE/TPR / TPU
|
Performance |
EPDM+PP-X |
TPE/TPR |
TPU |
||
|
TPV |
TPO |
SBS |
SEBS |
||
|
Tensile Strength |
Δ |
Ο |
Ο |
Ο |
◎ |
|
Compression permanent deformation(100℃,168H) |
◎ |
Ο |
Δ |
Δ |
Δ |
|
Operating temperature(℃) |
-60~135 |
-40~125 |
-20~80 |
-30~110 |
-30~120 |
|
Hot Air Aging (100℃,720H) |
◎ |
Ο |
X |
Δ |
X |
|
Oil Resistance,3#oil (125℃,70H,3#oil) |
◎ |
Δ |
X |
Δ |
Δ |
|
Acid and alkali resistance |
◎ |
Δ |
X |
Δ |
Δ |
|
Processing technology |
◎ |
◎ |
◎ |
◎ |
X |
|
◎:Excellent Ο:Good Δ: Ordinary Χ:Poor |
|||||
After comparison, it is not difficult to find, that there is a major difficulty in obtaining material parameters and properties that are applicable to a wide range of conditions.
So we need to choose the proper material for rail pad considering both costs and required performance of the local railway companies.
What is the standard for railway elastic pad?
Below are the standards of rail pads for different countries or organization.
British: EN 13481-2, EN 16730.
China: TB/T2626, HG/T 3328-2006
ISO: ISO 14837-1:2005, ISO/TS 14837-31:2017, ISO/TS 14837-32:2015; ISO 22074-1:2020, ISO 22074-2:2021, ISO 22074-3:2021, ISO 22074-4:2022, ISO 22074-5:2021, ISO 22074-6:2021, ISO 22074-7:2021.
UIC: UIC 864-5
NR(Network Rail): NR/L2/TRK/052; NR TWI 2C046; NR TWI 2S075
How to order rail pad?
On high-quality basis, Kunshan Alex Railway Fastening Co., Ltd could provide different types of rail pad according to different standards requirement.
Just send us the detailed dimensions of your rail pad or standard rail pad you get from any catalogues, we could choose the most proper material for your required rail elastic pads and submit in proper time.
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