What is the purpose of interlocking in railway signaling systems?

The purpose of interlocking in railway signaling systems is to prevent conflicting train movements by ensuring that signals and switches are coordinated to allow only safe routes to be set and to prevent routes from being set that could lead to collisions or derailments. Interlocking is a system of mechanical, electrical, or electronic circuits that controls the relationship between signals (which indicate whether a train is allowed to proceed) and switches (which control the direction of train movement). The interlocking system ensures that a signal cannot be cleared (set to allow a train to proceed) unless the route is safe and clear of other trains. This includes verifying that the switches are in the correct position for the route, that there are no conflicting routes set, and that the track is clear of obstructions. The interlocking system also prevents switches from being moved while a train is approaching or occupying the section of track controlled by the interlocking. This prevents a train from being inadvertently diverted onto an unsafe route. For example, if a train is approaching a junction, the interlocking system will ensure that the switches are set to direct the train onto the correct route and that no conflicting signals are cleared that could allow another train to enter the same section of track. This prevents head-on collisions, side collisions, and derailments that could result from conflicting train movements. Interlocking is a critical safety feature of railway signaling systems that helps to prevent accidents and ensure the safe and efficient movement of trains.