For safety reasons, speed limits are imposed on trains running on a railway line. Many factors can affect the speed limit of a particular line including the state of the track, the curvature of the track, the number of stations, the individual features of stations or junctions and the stopping distances of trains running on that track.
The purpose of speed restrictions for trains is to ensure safety. The speed limit is determined by various factors including the state of the track, the curvature of the track, the number of stations along the route, specific station or junction characteristics, and train stopping distances on that track.