There are mainly three kinds of rail fastening systems in the world, including blade fastening system, clamp fastening system and clip fastening system. Rail clamps are main fasteners that applied to clamp fastening system.
As a kind of fastener, rail clamp’s basic function is to fix rails on the sleepers, keep track stable and keep certain gauge distance from horizontal and vertical movement of rails. All in all, it is known as the key intermediate connection part.
Features of rail clamps
In blade fastening system and clip fastening system, their main fasteners are blade and clip that both have the common feature of elasticity. But in clamp fastening system, rail clamp itself is without elasticity, it belongs to rigid fastener. Sufficient rigidity contributes to the safety of rail transportation.
In China there are three main clamp fasteners designed in different history of rail. They are bolted type clamp in early times, 63 type clamps and 70 type clamps.
Due to limited levels of technology the designation of bolted type clamp embedded wooden screw in the concrete sleeper which connects fasteners and sleeper simply. This type has become the past. Now it has been very rare to use.
70 type clamps are applied to the concrete sleeper with ditch and it is suitable for rails for 43KG and 50KG. It can adjust gauge distance through replacement of different clamps in size. Connecting screw spike and sleepers is the form of sulfur anchor. At present in China, the new railway has been rarely laid, only in line with repairing. This kind of clamp fasteners is less elastic and clamping force reduces greatly, so it has been eliminated basically.
In the world the famous KPO fastening system is so in good performance that many countries apply it in their own rail tracks. KPO fastening system belongs to clamp fastening system. It includes KPO3, KPO5, KPO6 and KPO9 etc. Clamp has to be in accordance with DIN, AREAM standards, etc. rail clamp is usually made of low carbon steel or alloy steel by hot forging, rolling and casting.
It is used together with tie plate and bolt. In China it is made of steel of Q235 or 45#.
Also called hook bolt, it is used for the fastening of tie plate.
It is a base plate, the foundation of rail fastening system.
It is used to fasten tie plate to wooden sleepers. When used in the concrete sleeper, it is often together with the plastic dowel.
Normally it is used to distribute the load of fastener.
Surface treatment of rail clamps
The surface of rail clamps is often plain oiled, black oxide, galvanized, hot dip galvanized and sherardized. Rail clamps are commonly packed in wooden boxes or sacks and wooden pallets for 25KG per package.
In conclusion, rail clamps play the crucial role in clamp fastening system in railroad, it is still used in many countries and areas, many plants still produce them to meet the needs in China. It is the excellent invention for rail construction and development.