The 115RE steel rail, also widely designated as the TR57 rail (or 115 lb/yd rail), is a heavy-duty T-section profile manufactured in strict compliance with the American Railway Engineering and Maintenance-of-Way Association (AREMA) and ASTM standards. Weighing approximately 56.9 kg/m (114.7 lbs/yd), the 115RE rail is a foundational component of modern railroad infrastructure across North America, South America, and global heavy-industrial sectors.
This technical guide provides an objective overview of the dimensional tolerances, mechanical properties, metallurgical grades, and primary application fields of the 115RE rail profile.
1. Dimensional Specifications of the 115RE Rail
Engineering precision is critical to ensuring the longevity of rail systems and the compatibility of fastening components. The cross-sectional geometry of the 115RE rail is designed to distribute heavy axle loads efficiently while minimizing wear on both the railhead and vehicle wheels. The key dimensions of the standard AREMA 115RE profile are detailed in the table below:
| Dimensional Parameter | Imperial Standard | Metric Equivalent |
|---|---|---|
| Nominal Weight | 114.7 lbs/yd | 56.9 kg/m (56.89 kg/m) |
| Rail Height (H) | 6-5/8 in | 168.28 mm (168.3 mm) |
| Base/Bottom Width (B) | 5-1/2 in | 139.70 mm |
| Head Width (C) | 2-23/32 in | 69.06 mm (69.1 mm) |
| Web Thickness (E) | 5/8 in | 15.88 mm (15.9 mm) |
| Sectional Area | 11.22 sq in | 72.58 cm² |
Technical Note: While some simplified commercial data sheets may round the web thickness to 15.00 mm, the official AREMA standard specifies a design web thickness of 15.88 mm (0.625 inches). This exact dimension is essential for selecting matching elastic rail clips, joint bars (fishplates), and track bolts.
2. Material Grades and Mechanical Properties
To withstand high traffic volume and extreme structural stress, 115RE rails are rolled from premium-quality carbon steel. Depending on the operating environment and performance requirements, manufacturers typically offer several steel grades:
- Standard Carbon Steel (SS): Suitable for moderate-traffic mainlines, yards, and general industrial tracks.
- Head-Hardened Steel (HH): Heat-treated along the rail head to control the cooling rate, refining the microstructure into fine pearlite. This process provides superior hardness, wear resistance, and a longer service life in high-wear zones such as curves and heavy-haul routes.
- High-Strength Low-Alloy (HSLA) / Alloy Steel: Formulated with micro-alloying elements (such as chromium or vanadium) to enhance structural strength and fracture toughness without compromising weldability.
Common steel grades designated under ASTM and international equivalents include 900A, 1100, R260, 320Cr, and R350HT. These materials ensure that the rail maintains high tensile strength (typically ranging from 880 to 1180 MPa, depending on the grade and excellent resistance to plastic deformation.
3. Key Applications of 115RE (TR57) Rail
Due to its balanced geometric design and cost-to-performance ratio, the 115RE profile is widely applicable across various rail networks:
- Class I Freight Corridors: Capable of handling heavy axle loads and continuous freight traffic, particularly in North and South American transit lines.
- Mainline Passenger Routes: Provides the structural stiffness and tight tolerances required for high-speed passenger operations.
- Mining and Heavy-Haul Railways: Extensively used in coal, iron ore, and other mining haulage networks where heavy axle loads are routine.
- Ports, Terminals, and Crane Runways: Provides a stable foundation for dockside crane tracks and heavy freight transfer facilities.
- Industrial and Siding Tracks: Offers a durable option for factory rail links and maintenance yards.
4. Installation and Complementary Fastening Systems
The long-term performance and safety of a 115RE track system depend heavily on installation quality and the selection of compatible rail fasteners. The 115RE system typically uses:
- Tie Plates (Baseplates): Placed under the rail base to secure the rail to wooden ties or concrete sleepers, maintaining the correct rail cant.
- Fastening Mechanisms: Standard track spikes (cut spikes) or elastic fastening systems (e.g., e-clips or tension clamps) are used to control lateral movement and longitudinal creep.
- Joint Bars (Fishplates): Specifically designed 4-hole or 6-hole joint bars are used to connect rail segments when continuous welded rail (CWR) is not used.
5. Frequently Asked Questions (FAQ)
- What is the difference between 115RE and TR57 rail?
There is no structural difference between the two designations. "115RE" is the standard American designation defined by AREMA, indicating a weight of 115 lbs per yard. "TR57" is the metric equivalent name commonly used by European manufacturers like ArcelorMittal, where the "57" represents the nominal metric mass of approximately 57 kg per meter.
- Why is head-hardening (HH) important for 115RE rails?
Head-hardening is a heat-treatment process that increases the surface hardness of the rail head. It significantly improves wear resistance, reduces the rate of rail corrugation, and prevents premature fatigue cracking, making the rail far more durable in sharp curves and heavy-freight zones.
- What are the standard lengths available for 115RE rails?
The standard commercial lengths for 115RE rails generally range from 12 meters to 25 meters (or 39 feet to 80 feet). However, depending on specific project logistics and manufacturer capabilities, custom lengths can be supplied, and rails can be welded into continuous welded rail (CWR) strings for seamless track layouts.
- How is the weight of the 115RE rail calculated for shipping logistics?
The nominal weight of 115RE rail is 56.9 kg per meter (114.7 lbs/yd). To calculate the total weight of a shipment, multiply the total track length (in meters) by 56.9 kg, or the length (in yards) by 114.7 lbs. Proper planning ensures freight capacity limits are respected during transport.
