The Theoretical Weight of 136RE Rail
The theoretical weight of 136RE rail is 136 pounds per yard, which converts to approximately 67.5 kg per meter. This value is the standard metric used in North American Class I railroad engineering to determine track load capacity, ballast depth requirements, and procurement logistics. The AREMA 136RE rail is a heavy-duty profile designed to support the intense axle loads of modern freight locomotives and high-tonnage trains.
The section is also known by the designation TR68 in some international specifications, referring to its 68 kg per meter class.
AREMA Section Data
| Parameter | Value |
|---|---|
| Rail height | 185.70 mm |
| Base width | 152.40 mm |
| Head width | 74.60 mm |
| Web thickness | 17.50 mm |
| Section area | 85.90 square centimeters |
| Nominal mass | 67.5 kg per meter |
| Nominal weight | 136 lb per yard |
| Standard | AREMA |
Why the Weight Matters
Heavier rail acts as a more rigid beam, which deflects less under the weight of passing trains. This lack of movement prevents the ballast from shifting and the sleepers from grinding against the track bed, which are leading causes of track geometry failure. Choosing 136RE heavy rail over lighter profiles trades a higher initial material cost for significantly lower maintenance labor over the life of the infrastructure.
The 136RE section also provides a substantial wear buffer. Because there is more steel in the head of the profile, the rail can be ground repeatedly to remove surface fatigue without compromising the structural integrity of the track.
Mass Distribution Within the Section
The theoretical weight is distributed through the profile with the majority of the steel in the rail head to provide a deep wear surface. The head area is approximately 4.94 square inches, the web area about 3.57 square inches, and the base area about 4.84 square inches, totaling a section area of about 13.3 square inches. The metal is positioned to maximize the moment of inertia, allowing the rail to support axle loads of 35 tons or more without permanent deformation.
Rolling Quality and Verification
The section area is measured during the rolling process to ensure the rail is not under-rolled. A smaller area would mean a lower weight and a compromised load-bearing capacity. Precise dimensions also guarantee that the rail fits correctly into tie plates and fastening systems, preventing uneven wear and compatibility problems with standard AREMA fasteners.
When 136RE Is the Right Choice
136RE rail is optimized for heavy freight corridors, high-tonnage coal and grain lines, and other demanding mainline services. For light passenger rail or industrial trams, a lighter profile such as 115RE is usually more cost-effective because it does not require the extreme mass of the 136RE section.
FAQ
Q: What is the exact 136RE rail weight in kg per meter?A: The nominal value is 136 pounds per yard, approximately 67.5 kg per meter, which is the figure used in international shipping documents and metric engineering designs.
Q: How does the rail height affect the weight?A: The 136RE height of 185.70 mm requires a specific web thickness and head mass to maintain stiffness, which together produce the 136 lb per yard total.
Q: Are 136RE dimensions consistent across manufacturers?A: Yes. All 136RE rail must comply with the AREMA manual, so the profile remains consistent and rail from different batches can be joined seamlessly.
Q: Is 136RE too heavy for light-rail projects?A: Generally yes. Its weight is optimized for heavy freight, and lighter profiles such as 115RE are more economical for passenger and industrial light rail.
Q: Why is the section area important for quality?A: The section area is checked during rolling to prevent under-rolled rail. A smaller area means lower weight and reduced load-bearing capacity.
Q: What documentation should accompany a 136RE delivery?A: Mill test certificates verify the chemistry, mechanical properties, and dimensional compliance of each batch against the AREMA standard.
