The rail fastener is the part of the rail that is used to connect rails and sleeper functions by securing the rails on the sleeper, keeping the gauge and preventing the rails from moving longitudinally relative to the sleeper.
Including spike, rail pad under the rail and elastic or rigid buckle and so on. Fasteners should be able to long-term, effectively maintain the rail and the sleeper of the reliable connection, and under the action of the full play its buffer damping performance, delay the accumulation of residual deformation of the track. So it should have sufficient strength, durability and a certain degree of flexibility, but also simple structure, easy to install and disassemble. In addition, the pre-stressed concrete sleeper, the fastener should also have sufficient clip pressure and gauge, the level of adjustment.
Wooden Sleeper fastener
A coupling part for connecting rails and wooden sleeper on a sleeper rail. According to its connection rail, pad and wooden sleeper between the three is divided into: sub-liter and mixed sleeper.
Separate fasteners are to separate the fixed rails from the bolts or spikes of the fixed iron plate. Generally use the spike to the tie plate fixed on the sleepers, tie plate on the bearing slot, fixed rail bolts installed in the tie plate, and then use the clip or clip plate will be fixed.
The hybrid fastener consists of an tie plate and a spike. Use the hook spike (square) to connect the rails directly to the tie plate and the sleepers. Rail clip is small, in order to prevent the longitudinal crawling of the rail, the need for more anti-climb equipment.
Concrete Sleeper Fastener
The concrete sleeper rail is used to connect rails and concrete sleeper connections. Concrete sleeper due to the weight, stiffness of the characteristics of the fastener performance requirements are high, its clip pressure, flexibility, and adjustable are more stringent requirements. Concrete sleeper fastener, according to its structure can be divided into spring fastener, clip fastener, shrapnel fastener (see concrete sleeper fastener) three. According to the elasticity of the fastener itself can be divided into rigid fastener and elastic fastener . According to the concrete sleeper with or without the shoulder is divided into a pair of fastener and no clip fastener. China's concrete sleeper fastener, in the early use of the main clip and shrapnel two size. Arched shrapnel fastener due to arched shrapnel strength is low, easy to cause residual deformation, or even broken, so the Chinese railway is no longer used. The clip fastener due to the use of clip pieces, lack of elasticity, clip pressure is low, easy to use in the process of loosening. The current Chinese railway has been gradually replaced by the bc;i fastener. The buckle fastener is made of buckle as buckle, and the bending deformation and torsional deformation of the material are used. There is no problem of weakening the section, and the structure is reasonable. Therefore, it has become the main fastener of Chinese concrete sleeper rail. At present, the main fastener used for the spring type Ⅰ fasteners, with the development of heavy-duty high-speed railway, in recent years has developed a successful spring II, Ⅲ type fasteners and so on. Among them, type Ⅲ fastener without bolts without stopper fasteners.
The clip fastener is composed of clip plate, thread spike, spring washer, tie seat and cushion plate. The thread spike is anchored in the reserved hole of the concrete sleeper bearing table with sulfur cement mortar, and then the bolt fastening.
Clip fasteners have spring Ⅰ, Ⅱ, Ⅲ type. Projectile type Ⅰ by the ω ball, spiral spike, gauge baffle and rubber pad composition. Its clip pressure is insufficient, the ball is too small.
The shape of the clip type II is the same as that of the projectile type Ⅰ, and the stroke is not less than 10mm. The clip pressure is improved compared with the bucket type Ⅰ.
It is suitable for heavy traffic and high density transportation conditions. It has the advantages of high deduction pressure and good elasticity. In particular, it eliminates the concrete shoulder and eliminates the effect of the rail bottom in the lateral force The possibility of a transverse displacement occurs.
According to the requirements of rail transit, the new rail fasteners should have the following characteristics:
1) Have sufficient strength and durability.
Rail transit operation time is long, high traffic density, poor maintenance conditions, requiring rail fasteners must have sufficient strength and durability to ensure traffic safety.
2) Have a certain gauge and level adjustment performance.
Rail traffic using the overall rail bed structure, the line curve radius is small, the existence of wear and tear rail. This requires that the fastener should have a certain gauge, the level of adjustment performance to solve the curve of the rail wear and structural uneven settlement and construction errors caused by the gauge, rail level overrun.
3) Have good insulation performance.
Rail traffic is generally used as a return rail track, which requires fasteners must have good insulation properties, to prevent leakage of current through the fastener, resulting in structural steel and municipal pipeline corrosion.
4) Have good damping elasticity.
Subway and other urban rail transit through the residential area, the vibration and noise reduction requirements of environmental protection is very high, rail fasteners must have a good vibration performance, attenuation of orbital vibration, reduce noise transmission.
5) Have a certain general interchangeability.
Fastener structure should be simple, few parts, with a certain general interchangeability, low cost, easy construction and maintenance.