This Happen on almost every major railway station either it is junction or terminal due to following : 1. On junction there are many curves, track changing points, for safety reasons train have to be slow in that area. 2. read more
Trains have to slow down over points leading to branching/merging of tracks. If the train is on a clear main-line, it can go at full speed through the station. However, if it has to go through track loops or the platform line, the train must slow down to safely divert/merge at the points. read more