Rail Joints

Rail joints are the weakest part of the track. Due to discontinuity of rail in the horizontal & vertical plane, imperfection in the levels of rail heads at the joint & discontinuity in the wave motion of rail, joint suffer with severe blow under passage of wheels. The blow results in degradation of ballast, reduction in ballast resistance and affecting track parameter due to loose packing/ fastening.

Types of Joints

1) Suspended Joint

The rail ends are suspended between 2 sleepers and some portion of rail is cantilever at the joint. Due to cantilever action the packing under the joint sleeper get loose while movement of load. Suspended joint are very common and being adopted not only in Indian Railway but also in other countries of the world.

2) Supported Joint

The rails ends are supported directly on sleeper. It was earlier thought that by supporting the joint, wear & tear of rails will be less being no cantilever action, but in actual practice the joint was found to be high and running was found to be hard. A duplex sleeper is an example of supported joint.

3) Insulated Joint

Insulated joint are used at the ends of a track circuited section. A section of insulating material is fitted between the rail ends and an insulating sheet is interposed between the rails and fish pale. In welded track joint G3s and G3l are used.

4) Switch Expansion Joint (SEJ)

This joint is used at the ends of LWR / CWR track to accommodate the expansion and contraction of the breathing length. 

Fish Plate

The function of a fish plate is to hold the rails together both in horizontal and vertical planes with help of bolts. The name fish plate is traditionally given to this fitting as its section looks like fish.