In railway track structures, concrete sleepers have been widely used due to their high strength, good stability and long service life. The railway fastener system, as a key part connecting rails and concrete sleepers, plays a vital role in ensuring the safe operation of railways.
Common fastener system types
Spring clip fastener system
This is the most common type at present, using spring clips as buckling parts to fix rails. Among them, spring clip type I fasteners are composed of ω-shaped spring clips, spiral spikes, gauge baffles, baffle seats and elastic rubber pads. It has good elasticity and can effectively maintain the geometric shape of the track, but there are problems such as insufficient buckling pressure and small elastic range, and the spring clip design has insufficient safety strength reserve, which is not suitable for heavy-load transportation.
The structure of the spring clip type II fastener is similar to that of the type I, but the material of the spring clip is upgraded to 60Si2CrVA, with greater buckling pressure, high strength safety reserve, and small residual deformation. It is suitable for 60kg/m rail lines with type II or type III concrete sleepers, but the anti-rust and anti-loosening work is more cumbersome and is not suitable for high-speed lines.
The spring clip type III fastener is a boltless and shoulder-free fastener, which consists of an e-shaped spring clip, an embedded iron seat, an insulating gauge block, and a rubber pad. It has high buckling pressure, good elasticity, strong gauge holding ability, and less maintenance work. It represents the development trend of boltless and shoulder-free fasteners. However, it cannot be adjusted higher, and the gauge block is easily damaged on a small radius curve, and the buckling pressure will decrease after repeated use.
In addition, there are spring clip IV and V fasteners. Spring clip IV is used for high-speed ballasted tracks. The spring clip structure is optimized and the track gauge adjustment is more accurate. Spring clip V is improved on the basis of spring clip II, increasing the spring clip range and buckling pressure, and is suitable for high-speed ballasted tracks.
Clip plate fastener system
It consists of clip plates, threaded spikes, spring washers, iron seats and buffer pads. The threaded spikes are anchored in the reserved holes of the concrete sleeper support platform through cement mortar, and then the clip plates are fastened with bolts to fix the rails. The structure of this fastener system is relatively simple, but there is a certain gap in elasticity and buckling pressure compared to the spring clip fastener system. such as KPO fasteners system.
Spring clip fastener system
Spring clips are used as components for buckling rails, and the elastic deformation of spring clips can be used to provide buckling pressure. However, since the spring clip can only utilize the bending deformation of the material, its elasticity is usually not as good as the spring clip that can utilize both bending and torsional deformation. In practical applications, its scope of use is not as wide as the spring clip fastener system.such as Nabla fasteners system.
