Types of Railway Fastenings

Fastenings: Securing the Rails

Fastenings are crucial in securing the rails to the sleepers or ties. They include a variety of components such as clips, bolts, screws, and plates. 

Their function is to transfer the loads from the rails to the sleepers and further to the track’s substructure, to maintain the gauge, and to prevent twisting of the rails about the sleeper. 

The rail fastening should have the required clamping force and allow a certain freedom of movement and torsional resistance.

 Fastenings ensure the stability and alignment of the track while accommodating expansion and contraction due to temperature variations. 

These components resist the lateral and vertical forces exerted by moving trains, maintaining the integrity of the track structure.

There are various kinds of fastenings, and the old versions are being replaced by new fastening systems, although old fastening types remain in use in different parts of the world. 

The following table presents the types of fastenings, their elasticity property condition, their positive and negative sides, and the regions of their applications.

Hey back.

Heyback fastening is a Norwegian invention designed to provide secure and reliable fastening for railway tracks. It consists of a washer plate that is screwed into the sleeper and a clamp made of spring steel that tightly holds the rail foot against the plate. 

This innovative fastening system can be used on both wooden sleepers and concrete sleepers, offering versatility in track installations.

The primary purpose of Heyback fastening is to meet the demanding requirements of seamless tracks, particularly in terms of holding power, rail travel, and torsional resistance.

 Its implementation began on selected main lines in the mid-1950s, showcasing its effectiveness and reliability in rail infrastructure.

In the Heyback fastening system, the base plate is securely held in place within the sleeper using four rail screws. To ensure proper alignment and cushioning, a 3.5 mm-thick rubber spacer is inserted between the rail foot and the base plate. 

The rail is then firmly fixed to the base plate with the help of clamping springs, which are wrapped between strips on the upper side of the plate.

The Heyback fastening system has proven to be a valuable addition to railway track components, offering stability, durability, and resistance to various forces exerted on the rail. 

Its efficient design and secure installation make it a reliable choice for maintaining the integrity of railway tracks and ensuring safe and smooth train operations.

Rail spike

Rail spike fastening is a crucial component of railway track systems, used to secure the rails to the sleepers or ties.

 The forces transmitted from the rails to the ballast, including those from rolling stock, rail movement, and temperature changes, can act vertically, laterally, and along the rails simultaneously. 

To counteract these forces, the rail fastening system must provide the necessary clamping force, ensuring a strong connection between the rails and sleepers while resisting rail travel and twisting.

Over time, the design of rail fastenings has evolved from simple spike fasteners on wooden sleepers to more advanced systems on concrete sleepers.

 Initially, rail spikes were widely used to attach rails directly to the sleepers, often accompanied by steel underlay plates placed between the rail foot and the sleeper. 

As rail traffic increased, it became apparent that additional reinforcement was necessary. The dimensions of the underlay plates were gradually increased to enhance the stability and durability of the fastening system.

Rail spike fastening, which includes rail spikes and underlay plates, offers a straightforward and cost-effective solution. It is relatively easy to assemble and disassemble, and in freezing conditions, it can be supplemented with wedge plates or wedges for added stability. 

However, rail spike fastening does have some drawbacks. The holding power of the spikes is sometimes insufficient, resulting in movement between the rail components. 

This can lead to mechanical wear and an increase in track width. Moreover, the resistance to rail travel provided by rail spike fastening may not be adequate, necessitating the use of additional precautionary measures.

Elastic spike with plates:

The elastic rail spike is a type of fastening system used to secure rails, base plates, and sleepers in railway tracks. It consists of three spring nails that are driven into pre-drilled holes in the sleepers. 

The diameter of the holes varies depending on the type of sleeper, with pine sleepers typically having a diameter of 13 mm and beech sleepers having a diameter of 15.5 mm.

In a healthy sleeper, each nail exerts a holding force of approximately 5 kN, resulting in a total holding force of approximately 15 kN when three nails are used per plate. 

However, over time, the attachment of the nails in the sleeper deteriorates, leading to a decrease in holding power and increased rail travel resistance.

To mitigate these issues, a 3.5 mm-thick rubber spacer is placed between the rail foot and the base plate. Previously, wood fiber spacers were used, but the rubber spacer offers increased friction between the rail and the base plate. This helps to maintain stability and reduce rail movement.

It’s important to note that the use of spring spikes is not recommended in tracks that experience freeze-ups requiring wedging.

 Additionally, the repeated process of pulling out and hammering down the nails can further deteriorate the nail attachment and reduce the holding power over time.

Overall, the elastic rail spike provides a method for securely fastening rails, base plates, and sleepers in railway tracks, ensuring stability and reducing rail travel resistance.

K-fastening:

The K-fastening system is a widely used and classic screw fastening method employed on railway lines, particularly on wooden sleepers. It provides a reliable connection between the sleeper and the plate. 

The K-type fastening system requires the installation of an under-base pad beneath the ribbed plate, while a rail seat pad is placed under the rail foot. The rail is secured using the clip, ensuring proper fixation.

One of the notable features of the K-fastening system is its versatility, as it can be mounted on prestressed concrete sleepers as well. This flexibility allows for its application in various railway infrastructure projects. 

The system offers effective insulation between the rail foot and the sleeper, contributing to electrical and thermal insulation properties, which are essential in ensuring safe and efficient railway operations.

The components of a K-fastening system typically include rail clamps, rail screws, T bolts with washers and nuts, a tie plate, and dowels. These components work together to provide a robust and secure connection between the rail and the sleeper, contributing to the overall stability and longevity of the railway track.

Overall, the K-fastening system is a time-tested and reliable method used in railway construction worldwide. Its versatility, insulation properties, and availability of different clip options make it suitable for a wide range of railway applications.

Hambo:

The Hambo fastening is a railway fastening system that was originally developed in Sweden. It was created by combining the names of its inventors, Hammerin and Borup, resulting in the name “Hambo.” 

Although it was once widely used, particularly in the early 2000s, it has gradually fallen out of favor and is no longer extensively utilized.

The fastening consists of two hooks, which are attached to monolith slips or one-block sleepers. Each hook holds a smaller hook that secures the rail in place. 

Positioned between the rails and sleepers is an underlay plate made of insulating material, which serves as a buffer. This plate helps to provide insulation and prevent electrical conductivity between the rail and the sleeper.

The fastening system is designed to provide stability and secure the rail in place. The hooks, made of elastic steel, are cast into the sleeper, ensuring a durable and robust connection. A plastic spacer, approximately 5.5 mm thick, is placed between the hooks. This spacer has raised side strips on which the rail foot rests, offering additional support and preventing lateral movement.

Pandrol E-clip:

The E-clip fastening system is a resilient method of connecting railway tracks to sleepers, ensuring stability and accommodating rail movement. It consists of several components that work together to provide a secure and flexible connection.

At the core of the system is a backing plate with a loop that holds the E-clip in place. The E-clip, similar to a paperclip, exerts pressure against a plastic spacer on the upper side of the rail foot. 

This pressure, which can be as high as 1000 kp (1 ton), ensures a firm grip between the rail and the fastening system. To provide cushioning and insulation, a rubber spacer is placed beneath the rail foot.

When it comes to detaching the E-clip, it can be dislodged by applying force, such as with a sledgehammer. The E-clip is typically made of round spring steel and is available in different diameters to accommodate various applications. 

Coarser clips, often green, are used for attaching gears, while straight grooves are secured with finer clips, often red.

The installation of E-clip fastenings differs depending on the type of sleepers used. For wooden sleepers, the backing plate is secured with wood screws and spring washers. In the case of concrete sleepers, a simplified plate is precast into the sleeper during manufacturing.

The advantages of the Pandrol E-clip fastening system are numerous. It offers excellent vibration absorption, reducing stress and wear on the rail and sleeper. 

The resilient connection provided by the E-clip accommodates rail movement and expansion, enhancing track stability. The system utilizes Pandrol’s original design ‘e’ shape, which has set the industry standard for fastening systems. 

Being a threadless, self-tensioning system, there is no need to periodically check the torque. The system is also known for its durability, minimal risk of corrosion, and ease of installation on both concrete sleepers and in combination with base plates.

Pandrol Fastclip:

The Pandrol Fastclip fastening system is a highly regarded and resilient rail fastening solution designed for efficient installation and long-term performance. It consists of various components, including a baseplate, pre-assembled elastic clips, and bolts or clips for fastening.

The unique feature of the Pandrol Fastclip is its ability to be pushed perpendicular to the rail, allowing it to be snapped into three different positions.

 In the first position, it locks against the rail foot, providing a secure connection. In the second position, it parks to facilitate rail insertion. And in the third position, it allows for insulation change.

During the manufacturing of the sleeper, all fastening details are already put in place, making installation easier and more efficient. The pre-assembled nature of the clips eliminates the need for manual assembly and reduces installation time.

One of the key advantages of Pandrol Fastclip fastenings is their ability to absorb and dampen vibrations effectively. This superior vibration absorption helps reduce wear and tear on the rail and sleeper, ensuring long-term performance even under heavy loads and various track conditions.

The fastening system offers a high level of adjustability, both vertically and laterally, allowing for precise alignment and easy maintenance. It is designed for use on various track types, including ballastless tracks, and can be adapted to different railway applications such as light rail, metro, mainline, and high-speed tracks.

Additionally, the Pandrol Fastclip system is designed to provide efficient installation and minimize maintenance costs, resulting in maximized rail infrastructure uptime. With its captive design and reliable clamping force, the Fastclip fastenings offer a robust and durable connection between the rail and sleeper, ensuring the safety and stability of the track system.

W-fastening:

The W-fastening system, also known as the W System series, is a highly reliable and acknowledged “Elastic Rail Fastening System” used worldwide. It is comprised of five parts and offers exceptional performance and durability.

At the core of the W-fastening system is the W-shaped tension clamp with spring arms. These spring arms exert a constant clamping force on the rail, ensuring a secure connection to the sleeper.

 The rail is fastened to the sleeper using a dowel and rail screw, preventing any lateral tilting or deformation. The forces generated are effectively transferred to the sleeper and the ground through the angled guide plates.

One of the notable advantages of the W-fastening system is its simplicity and reliability. It is a low-maintenance system that can be installed quickly and easily. 

If necessary, all parts of the fastening system can be replaced, allowing for easy maintenance and repair. Additionally, the W-fastening system is suitable for use with elastic rail pads, further enhancing its performance and reducing vibrations.

The W-fastening system is designed to withstand heavy loads, with a resistance capacity of up to 22.5 tons of axle load. This makes it suitable for demanding applications such as heavy haul and high-speed railways. 

It has been extensively tested and proven in various conditions, including severe curves, wide temperature fluctuations, and heavy carloads.

In North America, Vossloh’s W System series offers a modern solution for ballasted concrete ties. The system utilizes the shoulders of the concrete tie to provide stability to the track and fastening system.

 This ensures efficient force transfer and minimizes structure-borne noise caused by passing trains. The W-fastening system has been successfully implemented in over 30 countries, covering a combined total of 1,900 track miles.

For conventional speeds, the W 21 is the ideal choice and has been widely adopted globally. It has a proven track record in various railway networks and is suitable for speeds typically found in standard operations. 

On the other hand, the W 21 HS variant, designed for high-speed applications, has been successfully tested at speeds of up to 155 mph, making it suitable for high-speed rail systems.

For heavy haul operations, the premier choice is the W 40 elastic rail fastening system. It is specifically designed to withstand extremely heavy carloads and maintain maximum stability, even in narrow bends and tight curves. 

The W 40 system has been successfully in service in North America since 2013 and has been installed on approximately 200 track miles.

Nabla:

The Nabla fastening system, specifically the NABLA Evolution, is a highly efficient direct rail fastening system designed to deliver superior performance, particularly in tracks with tight radius curves. 

With a proven track record spanning several decades, it is recognized for its ease of installation and maintenance, making it a reliable choice for rail networks.

The components of the Nabla fastening system consist of a Nabla clip, rail insulator, screw spike, nut, and spring washer.

One of the key advantages of the NABLA Evolution is its ability to maintain the track gauge, which significantly enhances the longevity of the assembly components. 

This feature ensures the stability and integrity of the track, leading to improved operational efficiency and reduced maintenance requirements.

The NABLA Evolution fastening system is suitable for a wide range of track types, including heavy haul applications. It offers not only improved electrical insulation but also exceptional lateral force absorption. 

The lateral insulator, which incorporates glass-reinforced material, provides enhanced mechanical strength, contributing to the system’s overall durability and reliability.

Widely used in Europe, the Nabla fastening system is renowned for its safety and reliability. It finds applications in various railway tracks, including Tram, LRT (Light Rail Transit), Metro, Main Line, and High-Speed tracks. 

The unique shape of the Nabla blade generates a dynamically stable toe load on the steel rails when the rail nut is torqued, ensuring secure and stable rail fastening.

Fist fastening:

The Fist Rail Fastening System is a type of railway fastening system that is designed to securely attach rails to sleepers or ties. It is a popular choice in various countries, including South America and Australia. 

The system consists of several components, including a spring steel clip, rail pad, and insulated retaining pin.

The spring steel clip plays a vital role in providing the necessary grip and holding the rail firmly in place. It is designed to withstand the forces and vibrations experienced by the rail, ensuring stability and preventing movement. 

The rail pad acts as a cushion between the rail and the sleeper, absorbing vibrations and reducing wear and tear on both components. It also helps distribute the load evenly, protecting the sleeper from excessive stress.

To ensure electrical insulation and to prevent stray currents, the Fist Rail Fastening System includes an insulated retaining pin. This pin helps maintain electrical isolation between the rail and the sleeper, ensuring safe and efficient operation of the railway.

The Fist Rail Fastening System is versatile and can be used with different types of sleepers, including wooden, steel, or concrete sleepers.

 It offers flexibility in terms of toe load and axle load requirements, allowing customization to suit specific railway applications.

Originally developed in Sweden, the Fist Rail Fastening System has gained popularity and is extensively used in various countries in Africa, such as South Africa, Zimbabwe, Botswana, Swaziland, and Namibia. 

Its reliable performance, ease of installation, and ability to withstand heavy loads and harsh track conditions make it a preferred choice in these regions.

SKL fastening

The SKL rail fastening system is a type of hot rail fastening system commonly used in the railway materials market. It consists of several components, including SKL rail clips, rail pads, screw spikes, tie plates, washers, plastic dowels, track bolts, and nuts.

One specific type within the SKL rail fastening system is the SKL-12 rail fastening system, which is typically used in ballastless tracks without concrete retaining shoulders. Its main structural features are as follows:

1. Separate screw holes: The ribbed plates have separate screw holes at both ends, which are connected to the railway sleeper/track plate using fork bolts.
2. T-bolt insert seat and retaining shoulder: The ribbed plate is equipped with a T-bolt insert seat and retaining shoulder. The elastic clip is fixed by tightening the nut of the T-bolt.
3. Horizontal and lateral adjustment: Different sizes of eccentric heart taper pins are used for horizontal and lateral adjustment of the rail.
4. High and low adjustment: High and low setting plates are inserted to achieve high and low adjustment of the rail.

The SKL rail fastening system, also known as the Vossloh clip fastening system, is widely used in heavy haul, high-speed, and standard track applications. 

It provides stability to the track, accommodates rail movement, and offers easy maintenance. The system is cost-effective due to the absence of a base plate, and it is compatible with various types of SKL rail clips, such as SKL1, SKL3, SKL12, and SKL14.

Benefits of the SKL rail fastening system include:

1. Stability: The system provides stability to the track and allows for the transfer of forces generated by passing trains.
2. Easy maintenance: The screw design facilitates maintenance work and helps reduce maintenance costs.
3. Cost-effectiveness: The absence of a base plate results in lower manufacturing costs.

The SKL rail fastening system is widely used in concrete sleepers on ballast tracks worldwide. It offers a permanently elastic fastening, good creep and torsion resistance, and high tilting stability. 

The system is designed for long service life and requires low maintenance. Different configurations and options are available, such as dual gauge and turnout sleepers, as well as theft-resistant screw heads.

KPO rail fastening

The KPO clamp rail fastening system is a widely used clamp system for railway tracks, especially for crane rails. It offers better clamping force and a longer lifespan compared to normal fastening systems. 

The KPO system has gained popularity worldwide due to its safety and stability performance.

The KPO fastening system includes various types of clamps, such as KPO3, KPO5, KPO6, and KPO9, which provide excellent clamping force. 

These clamps are designed to securely hold the rail in place while allowing necessary longitudinal movement. The KPO clamps are fastened to the rail ties using anchor bolts.

The components of the KPO rail fastening system include:

1. KPO Clamp: The KPO3, KPO6, and KPO9 clamps are key components of the fastening system, providing the necessary clamping force to secure the rail.
2. Screw Spike: The Ss8 screw spike is used to fasten the rail to the sleeper or tie plate.
3. Rail Dowel: The Sdu9 rail dowel is used to provide additional stability and support to the rail fastening system.
4. Bolt, Nut & Washer: The Hs32 bolt, nut, and washer are used for securing the various components of the fastening system.
5. Rail Pad: The rail pad, according to customer specifications, is used to provide cushioning and reduce vibration between the rail and sleeper.
6. Tie Plate: The tie plate is an essential component that distributes the load from the rail to the sleeper or ballast.

The KPO rail clip, also known as a rail fixing clip, is a key component of the KPO fastening system. It ensures the lateral position of the rail while allowing necessary longitudinal movement. 

The rail clamp features a mechanical lock that keeps the rail in position, combined with a vulcanized synthetic elastomeric nose that accommodates longitudinal rail movement. Rail clamps are typically fastened to the rail ties using anchor bolts.

The KPO rail clip is adjustable, self-blocking, and offers high clip strength. It is especially suitable for crane tracks on steel girders or concrete foundations with steel sole plates. 

The height of the rail clip is variable, allowing for compatibility with different rail types. It is designed to accommodate rail types ranging from 10kg/m up to 56kg/m, offering versatility in rail applications.