Rail clip, also called elastic rail clip, it is used to fasten the rail tracks with railroad spike, rail pad, track bolt, rail joint bar together. It is also usually used as a part of rail fastening system. There are huge demand of rail clips on the railway line, about 7000pcs per kilometer, which is directly related to rail safety.
What’s the function of rail clip? Rail track supports vehicle and is fixed to the railway sleeper by rail fastening system. As the core part of rail fastening system, the bending and distortion of rail clip will produce crimping force on the rail track, which ensure the reliable connection between rail tracks and keep the integrity of rail track. Besides, the rigid contact of vehicle and rail track will cause vibration, the elastic structure of rail clip can absorb the impact energy during the train operation, reduce the shocking. The elastic rail clip works under the repeated alternating stress. It bears various effects such as bending, torsion, fatigue and corrosion. When the vehicle passes, it also bears extremely high instantaneous impact load.
With the increase of the axle load of railway vehicles and the improvement of train running speed, as well as the development of urban rail transit and subway, the rail clip, as a key link of the track structure, are also constantly developing, and its importance has attracted more and more attention from various countries. It needs elastic rail clips with different performance to meet the requirements of different track. For example, in the conventional line, it requires elastic rail clip to meet the needs of heavy load and high-speed lines. However, in the seamless track of viaduct, in order to reduce the interaction between the rail and the bridge, the fastener resistance is required to be small, the elastic rail clip is guaranteed to have a low degree of steel, so as to ensure that the buckle pressure loss caused by the compression of the underlayer of the rail when the train passes, and the fastener is not loose.
According to specific situation and habit, various countries adopts different standard of rail clips to apply for development of railway. Typically, the Pandrol series of rail clip is the most famous brand among rail clip types. PR- clip, E-clip are widely separated to America, Canada, India and other countries.
In German, HM-type rail fastening system is very popular, it adopts SKL-clip. Based on the good effect, it is applied to a lot of countries and regions.
Dutch DE type railway fastening system and FIST rail fastening system all adopt rail clips, they all have good application.Japan and France adopts clips as rail fastening system, Nabla rail fastening system and 102 type fastening system are hot on the market.
For the spring blade type clip, It is relatively easy to make use of the bending deformability of the material, and the cost is often relatively low. However, due to the openings for rail bolt, stress concentration is easy to occur in this part, and the maximum bending moment of surface is exactly the weakest area. The arch elastic clip fastening developed in China at the early stage was found to be easily broken when bolts were tightened, and the vibration generated during train passage made the elastic pieces loose, and even some nuts withdrew from the bolts. Another gauge baffle under vibration is easy to climb to the bottom of the rail, contribute to a widening rail gauge.