What Is an SS Series Sleeper Screw?
The SS series sleeper screw with washer is a commonly used fastener in railway tracks, specifically designed to securely connect steel rails to wooden or concrete sleepers. The screw head has a square or rectangular shape, and the washer provides extra holding power and an anti-loosening effect. The screw is driven through the base plate or directly into the sleeper, and the thread grips the sleeper material so that the fastening stays tight under vibration and changing loads. Special dimensions or higher strength materials can be produced as custom orders according to the requirements of the project.
Main Types in the SS Series
The SS series covers a range of screw spike products for different sleeper and base plate configurations. The square head screw spike is the classic form for timber sleepers, the hexagon head screw spike suits mechanical driving and repair work, and other head types are available for specific fastening systems. The series is also referenced by common codes such as SS5, SS8, SS23, SS25 and SS35. The table below shows representative models with their nominal sizes and weights.
| Model | Specification | Weight in kg per pc | Surface | Standard |
|---|---|---|---|---|
| SS1/130 | M22 by 130 mm | 0.451 | Zinc, plain or black oil | UIC, AREMA, JIS, GB or per request |
| SS1/150 | M22 by 150 mm | 0.478 | Zinc, plain or black oil | UIC, AREMA, JIS, GB or per request |
| SS2/180 | M22 by 180 mm | 0.595 | Zinc, plain or black oil | UIC, AREMA, JIS, GB or per request |
| SS5/150 | M24 by 150 mm | 0.545 | Zinc, plain or black oil | UIC, AREMA, JIS, GB or per request |
| SS6/130 | M26 by 130 mm | 0.658 | Zinc, plain or black oil | UIC, AREMA, JIS, GB or per request |
| SS6/150 | M26 by 150 mm | 0.702 | Zinc, plain or black oil | UIC, AREMA, JIS, GB or per request |
| SS7/180 | M24 by 180 mm | 0.636 | Zinc, plain or black oil | UIC, AREMA, JIS, GB or per request |
| SS8/140 | M24 by 140 mm | 0.528 | Zinc, plain or black oil | UIC, AREMA, JIS, GB or per request |
| SS8/150 | M24 by 150 mm | 0.548 | Zinc, plain or black oil | UIC, AREMA, JIS, GB or per request |
| SS8/160 | M24 by 160 mm | 0.568 | Zinc, plain or black oil | UIC, AREMA, JIS, GB or per request |
| SS23/160 | M23 by 160 mm | 0.645 | Zinc, plain or black oil | UIC, AREMA, JIS, GB or per request |
| SS24/165 | M24 by 165 mm | 0.590 | Zinc, plain or black oil | UIC, AREMA, JIS, GB or per request |
| SS25/165 | M25 by 165 mm | 0.625 | Zinc, plain or black oil | UIC, AREMA, JIS, GB or per request |
Manufacturing Process
The SS series sleeper screw is produced through a controlled process chain: raw material inspection, wire drawing, cutting, head forming, heat treatment, surface treatment, final inspection, packing and shipment. Heat treatment is the step that sets the mechanical properties of the screw, giving it the strength to hold the fastening together and the toughness to survive installation. Surface treatment such as zinc plating or black oil protects the screw from corrosion in the sleeper environment.
Application Scenarios
SS series sleeper screws are used wherever rails must be fixed to sleepers through a base plate. They are found in mainline timber-sleeper track, concrete-sleeper track with plastic dowels, turnouts and crossing areas, and industrial sidings. The choice of diameter and length depends on the sleeper thickness, the base plate design and the pulling force required by the fastening system. For concrete sleepers, the screw is usually combined with a plastic ferrule cast into the sleeper so that it can be removed and re-used during maintenance.
Selection and Maintenance Points
Select the screw diameter according to the fastening system and the rail section, and the length according to the sleeper thickness and the embedment depth required. Match the head shape to the driving tooling used on site, and specify the surface treatment according to the climate, with zinc or hot-dip galvanizing preferred in humid or coastal areas. During maintenance, retighten screws that have loosened, replace damaged washers, and check the screws for corrosion and thread wear.
Common Misconceptions
A common misconception is that a screw spike and a dog spike are interchangeable. A screw spike is threaded and grips the sleeper like a screw, giving a much higher pull-out resistance and allowing removal and re-installation, while a dog spike relies on friction and is mainly for timber sleepers. Another misconception is that the model number defines the thread diameter; for example SS1 uses an M22 thread and SS5 uses M24, so the specification must always be confirmed. It is also often assumed that the washer is optional; the washer spreads the bearing pressure and prevents the head from loosening.
FAQ
Q:What is an SS series sleeper screw used for?A:It securely connects the steel rail to wooden or concrete sleepers as part of the rail fastening system.
Q:What is the head shape of an SS sleeper screw?A:The head is square or rectangular, with hexagon heads also available in the series.
Q:Why is a washer used with the sleeper screw?A:The washer provides extra holding power and an anti-loosening effect under vibration.
Q:What sizes are available in the SS series?A:Common models range from SS1 at M22 by 130 mm up to SS25 at M25 by 165 mm, with other sizes on request.
Q:Which materials are used for sleeper screws?A:Typical materials are Q235, 45# and 55# steel, with surface options of zinc, plain or black oil finish.
Q:Which standards apply to SS series screws?A:Screws are produced to UIC, AREMA, JIS and GB standards or according to customer requests.
