Railroad Metal and Rail Clips

The integrity and safety of railway systems depend heavily on the quality of their components. Among the most critical are the rails themselves and the fastening systems that secure them. The specific type of railroad metal used for the tracks must possess exceptional strength, durability, and resistance to wear to withstand the immense forces exerted by modern trains. Equally important are the rail clips, which are vital components of the railway fastening system, ensuring the rails remain fixed to the sleepers and maintain the correct gauge. This guide delves into the detailed specifications of both railroad rails and the various types of elastic rail clips used in track construction.

Specifications for Common Railroad Metal Sections

The selection of a rail profile is determined by factors such as axle loads, traffic density, and desired track speed. Standards bodies like the American Railway Engineering and Maintenance-of-Way Association (AREMA) provide precise specifications for these profiles to ensure interoperability and safety. The steel used for this railroad metal is typically a high-carbon or alloy steel, often heat-treated to enhance its mechanical properties. Key characteristics include high tensile strength, excellent wear resistance, and sufficient toughness to prevent brittle fractures. Below are the specifications for several widely used AREMA rail sections.

AREMA 115RE Rail Specifications

The 115RE rail is a common profile used in North American freight and transit lines. It is designed to offer a good balance between weight, strength, and cost-effectiveness.

Mechanical Properties of 115RE Rail Steel:

Dimensional Specifications for 115RE Rail:

AREMA 132RE / 136RE Rail Specifications

The 132RE and 136RE sections are heavy-duty rails designed for high-tonnage freight lines where durability and a long service life are paramount. The slightly heavier 136RE profile provides increased head wear capacity and structural stiffness.

Mechanical Properties for Heavy Rail Steel:

Dimensional Specifications for 136RE Rail:

AREMA 141RE Rail Specifications

Developed for the most demanding applications, the 141RE rail is used on routes with extremely high axle loads and traffic density. Its robust profile offers maximum resistance to wear and fatigue, making it suitable for challenging curves and steep grades.

Dimensional Specifications for 141RE Rail:

The Role and Specifications of Rail Clips in Fastening Systems

Rail clips are a crucial part of the railway fastening system, designed to secure the rail to the sleeper or baseplate. They generate a consistent clamping force that prevents the rail from moving vertically or horizontally, maintaining the track gauge and controlling the longitudinal forces caused by thermal expansion and train dynamics. Elastic rail clips are the most common type, manufactured from spring steel to absorb vibrations and shocks from passing trains.

E-Type Elastic Rail Clips

E-type clips are one of the most widely used fasteners globally due to their simple design, effectiveness, and ease of installation. They are manufactured from high-quality spring steel and are available in various sizes to fit different rail sections and fastening systems.

Specifications for Common E-Type Clips:

The manufacturing process for these clips involves heating the spring steel bar, forming it into its characteristic shape, and then quenching and tempering it to achieve the desired hardness and elasticity. This ensures the clip can withstand repeated loading and environmental exposure without losing its clamping force.

SKL Tension Clips

SKL (Spannklemme) tension clips are another popular choice, particularly in European and Asian railway networks. They are part of a complete fastening system that typically includes a screw spike, a plastic dowel, and an angled guide plate. This system allows for precise adjustments and provides excellent stability.

Specifications for Common SKL Clips:

The SKL system is highly regarded for its ability to maintain longitudinal restraint and its resistance to fatigue. The design allows the rail to “breathe” under thermal stress while keeping it securely fastened, reducing the risk of track buckling.

Other Types of Rail Clips

Beyond E-type and SKL clips, several other designs are used for specific applications.

• Fast Clip System: This design features a pre-assembled clip and toe insulator, allowing for rapid, mechanized installation. The clip is driven perpendicularly onto the rail, significantly reducing installation time and labor costs.
• Deenik Clip: A robust clip often used in heavy haul or high-speed applications, known for its high clamping force and durability.
• PR-Type Clip: A traditional clip design used in various international systems, valued for its reliability and long history of performance.

The material for these specialized clips is typically a silicon-manganese or chrome-silicon spring steel alloy, chosen for its excellent fatigue life and ability to retain elasticity over millions of load cycles. Each clip can provide a clamping force of approximately 2,500 pounds, which is critical for managing the immense forces generated by temperature changes in continuous welded rail. Without the consistent restraint provided by these elastic fasteners, tracks would be far more susceptible to derailment-causing events like pull-aparts or buckling. The innovation of elastic rail clips has been a transformative development in modern railway engineering, enabling safer and more reliable operation on a global scale.