A Switch is an arrangement that enables the train to change its track so that it proceeds in the correct direction. This SEJ is a device, installed at the end of LWR/CWR, to allow the longitudinal movements in the breathing length due to temperature variations or we can say it is an arrangement that compensates with the natural changes in the track due to temperature variations and protects the technical standard dimension of the same. This arrangement ensures that there is no considerable variance in the parameters of the track so that there is no hindrance is created in the passage of the wheel over it. Both expansion and contraction are dealt with by the SEJ