What Are The Technical Specifications And Dimensions Of 115RE (TR57) Rail?
Jun 12, 2026
115RE rail (frequently designated as the TR57 rail or 115 lb/yd rail) stands as one of the most widely implemented heavy-duty tee-section rail profiles in modern railway networks. Standardized under the guidelines of the American Railway Engineering and Maintenance-of-Way Association (AREMA), the 115RE rail is designed to balance weight, bending strength, and overall manufacturing cost. It is a critical component in heavy-haul freight lines, high-density mainline corridors, passenger transit tracks, and industrial rail yards across North America, South America, and global transit networks.
This technical guide details the precise geometry, metallurgy, mechanical parameters, and system accessories associated with the 115RE rail profile to provide a trusted resource for railway engineers, contractors, and procurement departments.
1. Classification and Metal Distribution Analysis
The nomenclature "115RE" denotes a rail with a nominal unit weight of 115 pounds per yard (specifically 114.38 lbs/yd, or 56.89 kg/m). The "RE" designation represents the standard profile designed by the AREMA (or former AREA) committees, while its international equivalent "TR57" reflects its European and global classification within the 57 kg/m transport rail family.
To resist fatigue and accommodate dynamic wheel loading, the physical cross-sectional area of the 115RE rail is systematically distributed among its three key components:
- Rail Head (34.96%): Composed of 2,536 mm² of steel, designed to optimize the wheel-rail contact zone and withstand wear from heavy axle loads.
- Rail Web (26.63%): Composed of 1,931 mm² of steel, providing vertical stiffness, lateral stability, and exceptional resistance to torsional deformation and impacts.
- Rail Base (38.41%): Composed of 2,786 mm² of steel, offering a wide footprint to distribute load stress evenly over railroad ties (sleepers) and prevent track overturning.
| 115RE Rail | 2 | /% |
|---|---|---|
| 2536 | 34.96 | |
| 1931 | 26.63 | |
| 2786 | 38.41 |
2. Standard Dimensions and Geometrical Section Properties
All dimensional attributes of the 115RE rail conform to the tolerances established by AREMA and ASTM A1 standards. Below is a detailed breakdown of its dimensional measurements and structural section properties:
| 168.28 mm | 6-5/8 inches | |
| 139.70 mm | 5-1/2 inches | |
| 69.06 mm | 2-11/16 inches | |
| 15.88 mm | 5/8 inches | |
| 72.58 cm² | 11.22 in² | |
| 56.9 kg/m | 114.38 lbs/yd | |
| 27.26 x 106 | 65.5 in⁴ | |
| 2.95 x 10⁵ mm³ | 18.0 in³ | |
| 3.59 x 10⁵ mm³ | 21.9 in³ | |
| 75.95 mm | 2.99 inches |
3. Metallurgical Composition and Mechanical Specifications
The performance of the 115RE rail in severe operational environments relies directly on its chemical composition and mechanical heat-treatment processes. High-carbon steels or low-alloy steels are utilized to balance hardness and ductility.
3.1 Chemical Composition (AREMA Standards)
The chemical boundaries for standard and high-strength 115RE rail steel grades under AREMA criteria include the following parameters:
| Carbon Steel (Standard Strength - SS) | 0.74 – 0.86 | 0.75 – 1.25 | 0.10 – 0.60 | 0.020% | 0.020% |
| Low Alloy Steel (Standard Strength - SS) | 0.72 – 0.82 | 0.80 – 1.10 | 0.10 – 0.50 | 0.020% | 0.020% |
| 0.72 – 0.82 | 0.70 – 1.25 | 0.10 – 1.00 | 0.020% | 0.020% | |
| 0.72 – 0.82 | 0.70 – 1.25 | 0.10 – 1.00 | 0.020% | 0.020% |
3.2 Mechanical Properties and Hardness
To endure the severe friction and impact of heavy axle loads (often up to 35 tons), modern 115RE rails undergo precise thermomechanical treatment (head hardening). Below are the key mechanical performance benchmarks across different AREMA steel grades:
| 511 MPa (74 ksi) | 983 MPa (142.5 ksi) | 10% | 310 HBW | |
| 724 MPa (105 ksi) | 1069 MPa (155 ksi) | 10% | 350 HBW | |
| 828 MPa (120 ksi) | 1179 MPa (171 ksi) | 10% | 370 HBW | |
| 552 MPa (80 ksi) | 1014 MPa (147 ksi) | 8% | 325 HBW | |
| 828 MPa (120 ksi) | 1179 MPa (171 ksi) | 10% | 370 HBW |
4. Key Engineering Advantages of 115RE Rail
Track engineers favor the 115RE rail profile for several technical and operational reasons:
- The engineered height-to-base ratio manages the extreme dynamic stresses of heavy freight trains while protecting the track bed from early degradation.
- Utilizing head-hardened (HH) microstructure options significantly minimizes plastic deformation, corrugation, and rolling contact fatigue (RCF) on sharp curves and switch-backs.
- Manufactured in alignment with universal AREMA and ASTM standards, 115RE rail has high compatibility with standard OTM (Other Track Material), simplifying procurement and joint maintenance operations.
5. Standard Applications and Accessories
The 115RE rail is extensively installed in mainline tracks, heavy-haul freight networks, mining railroad lines, port terminals, and curves where high structural integrity is required. To ensure a stable assembly, the rail utilizes standard matching accessories:
- Available in standard 24-inch (4-hole, approx. 68 lbs/pair) and 36-inch (6-hole, approx. 102 lbs/pair) configurations.
- Standard 1-inch x 6-inch high-strength bolts designed to withstand longitudinal expansion forces.
- Compatible with classic railroad cut spikes or modern elastic rail fasteners (e-clips) and tie plates to maintain track gauge.
6. Frequently Asked Questions (FAQ)
What does the "115" and "RE" mean in 115RE rail?
"115" indicates the nominal weight of the rail, which is 115 pounds per yard (approx. 56.89 kg/m). "RE" stands for the American Railway Engineering (AREMA) committee that designed the rail's standardized profile.
How does 115RE compare to 136RE rail?
The 136RE rail is heavier (136 lbs/yd or 67.5 kg/m) and taller than the 115RE rail. While 136RE rails are preferred for class-1 heavy-haul freight corridors carrying extreme axle loads over 35 tons, 115RE rails provide a more cost-effective solution for standard mainline traffic, passenger transit, subways, and industrial tracks.
Is 115RE rail suitable for weld-free installations?
Yes. 115RE rails can be ordered with pre-drilled fish bolt holes (typically 1-1/8 inch diameter holes) to utilize standard mechanical joint bars. However, they are also highly compatible with aluminothermic (thermite) or flash-butt welding to form Continuous Welded Rail (CWR) systems for high-speed or low-maintenance tracks.
What are the standard lengths available for 115RE rail?
Under North American standards, the common standard lengths are 39 feet and 80 feet. For international projects, manufacturers typically supply 115RE rails in lengths varying from 12 meters to 25 or 30 meters, depending on site logistics and shipment constraints.
