Railroad fastening systems typically receive little attention outside of the industry. Most of us tend to focus on the design of the trains themselves or shiny new stations that feature the latest consumer technologies. Yet railroad fastening systems are equally important. They serve to hold tracks safely and securely in place, while advancements in fastening technology have facilitated widespread railway expansion. In this article, we will take a closer look at the key components of railway fastening systems.
What is a Rail Fastening System?
Rail fastenings are devices that are used to secure running rails into baseplates or chairs or directly to sleepers, bearers, or other rail supports. They ensure that rails remain fastened to sleepers, bearers, or other rail supports and therefore play an integral role in railroad construction.
A rail fastening system then is a method of fixing rails to railroad ties or sleepers. A typical rail fastening system includes rail anchors, rail tie plates, chairs, spikes, screws, bolts, and fasteners.
Rail Fastening Systems: A Brief History
When most of us think of the earliest railways, we picture steam-based locomotives and the roles that they played throughout the Industrial Revolution. Yet rail systems have been in existence for several thousand years. The Post Track, a prehistoric causeway in the valley of the River Brue and the Somerset Levels in England, is one of the oldest known constructed trackways and dates back to 3838 BC.
It was not until 1515 that wooden rails were adopted. The Reisszug, a railway located in Austria, featured wooden rails and a haulage rope that was operated by human or animal power using a treadwheel. Remnants of the 500-plus-year-old Reisszug still exist today.
Early wooden rails were fixed to wooden sleepers using pegs or nails. The pegs or nails were inserted through holes in the rails. In the 18th century, cast iron rails came into use. Holes were made directly into the rails to allow them to be fixed to a support system. When stone block sleepers were used, nails were driven into a wooden block which was inserted into a recess in the stone block. It was not until the very end of the century that the first chair for a rail was used, attaching to the vertical web with bolts.
In the 1830s, Robert L. Stevens invented a flanged “tee” rail. The rail had a flat bottom and required no chair. This became the standard in North America and was later used with tie plates. Other countries eventually adopted the flanged T rail, but differences in fastening methods remain.
Components of a Rail Fastening System
Rail Chair
A rail chair consists of 2 jaws and a rail seat. It is installed between the rail sleeper and rails, fixed with screws, and locked with a steel key. The rail chair distributes the load from the rail to the sleepers to achieve uniform distribution.
Rail chairs come in various shapes and sizes, depending on the type of rail and sleeper being used, as well as the specific requirements of the railway.
Rail Clip
A rail clip helps to fasten steel rails to railway sleeps. The rail clip ensures a reliable connection, helps maintain the integrity of the track when temperature expands, and absorbs the shock produced by the train. Given the wide range of applications, there are many types of rail clips. Some of the most commonly used include E-type rail clips, SKL rail clips, and fast clip fasteners.
Rail clips are an important part of the rail fastening system and play a critical role in ensuring the safety and reliability of railway tracks. Properly designed and installed rail clips can help reduce maintenance costs, minimize the risk of derailment, and prolong the lifespan of the railway infrastructure.
E-Type Rail Clip
An elastic rail fastening, or E-clip, is a spring-loaded clip that ensures permanent elastic clamping. The plates are mounted on the sleepers with 4 coach screws and double spring washers. The E-clip provides a secure grip on the rail while also allowing for movement and vibration. This helps to reduce stress on the rail and extend its lifespan.
SKL Rail Clip
SKL rail clips are tension clamps that ensure permanent elastic clamping to fasten turnout parts onto concrete bearers. The clamps fasten to baseplates that are mounted onto the concrete using screws and plastic dowels.
Fast Clip
Fast clip fasteners are a newer type of rail fastening system. It is shoulder-free and bolt-free, has fewer spare parts, and features a compact structure. The base is pre-embedded when the sleeper is made, and the elastic clip is pressed against the rail by inserting it into the embedded base.
Rail Ties or Sleepers
Railway ties or sleepers sit between two rail tracks to maintain the correct gauge. Early ties were made of wood, such as oak, karri, and jarrah. Wooden ties are still used but are only suitable for low-speed train lines. Some of the advantages of wooden ties or sleepers are that they are easy to manufacture and are naturally electrically insulated.
Steel and concrete sleepers are more common. Steel sleepers can handle heavy loads and can be designed to suit a broad range of track specifications. Concrete is the lowest cost, requires less maintenance, and provides a longer service life.
The tie plate, also referred to as a sole plate or base plate, is located between the railroad tie or sleeper and the steel rail. The tie plate is typically fixed to the sleeper by railroad spikes or rail bolts that are inserted through the holes in the plate. The main function of the tie plate is to distribute the load and hold the rail in a gauge.
Rail Pad and Rail Insulator
The rail pad is an elastic polyurethane mat that is placed between the rail and the sleeper. The pad protects the top of the sleeper from vibrations and wears while helping to distribute the load.
Rail insulators, or rail nylon insulators, are used to modify rail gauges and electrically insulate rails, clips, and bolts from the interior of a concrete sleeper. The insulator serves the same function as a rail pad but is thicker.
Spikes, Screws, and Bolts
Rail spikes are large nails with offset heads that are used to secure rails and base plates to sleepers in the track over the ballast. Rail spikes are essentially chisel-shaped with flat-edged points. The spikes are driven with the edge perpendicular to the grain, giving greater resistance to loosening. A dog spike is like a rail spike but features a pointed penetrating end, and the rail head has two lugs on each side that resembles a dog’s head.
Chair Screws
Chairs screws, or coach screws, are large metal screws that are used to screw the baseplate or the rail directly into the sleeper. Chair screws cost more to manufacture than rail spikes but provide twice the fixing power and can be used in combination with spring washers.
Fang Bolts
Fang bolts, or rail anchor bolts, are more effective than rail spikes and chair screws. They are more resistant to loosening due to vibrations. They fix rails or chairs to sleepers and are inserted through a hole in the sleeper with a fanged nut that bites into the lower surface of the sleeper.
Rail Plastic Dowel
A rail plastic dowel, also referred to as a rail plastic sleeve or concrete insert, serves as the fastening foundation. It is pre-inserted into the concrete sleeper before assembling the rail fastening system parts. The dowel ensures a good connection between the rail fastening system and the concrete sleeper, as well as insulating the fastener parts from the ties.
Spring Spikes
Spring spikes, or elastic rail spikes, is a two-pronged U-shaped staple-like spike that is bent to resemble an M. A spring spike holds a rail down to prevent tipping and secures the baseplate to the sleeper. They are commonly used with flat-bottomed rails, baseplates, and wooden sleepers.
Railroad Safety
Railroad fastening systems are critical components of safe railroad travel. They ensure that tracks remain fixed and that they can withstand significant vibration and heavy loads. But in addition to accidents associated with railway travel, hazardous spills from the loading and unloading of liquids also pose significant safety risks.
Facilities are required to have spill-prevention procedures in place. The main form of spill prevention is railcar track pans, and SafeRack offers a complete range of railroad track pans and spill containment systems that are SPCC and EPA-compliant and safely capture hazardous spills from railcars. Our Polyethylene track pans and Metal railcar track pans are used globally to protect from accidental spills at railcar wash facilities, railroad tank car loading areas, and locomotive fueling stations.
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Moreover, workers tasked with climbing on top of tankers to load and unload potentially hazardous substances face substantial risks. SafeRack’s OSHA-compliant railcar gangways eliminate the need to climb on tankers and ensure that workers are protected from dangerous falls with safety cages that fit seamlessly over tanker hatches.
Report an oil or chemical spill.
For emergencies and other sudden threats to public health, such as oil and/or chemical spills, radiation emergencies, and biological discharges, call the National Response Center at 1-800-424-8802. Learn more at epa.gov
