A signal cabin is a central control point for signals and points on a railway line. Early signalling was very primitive and uncoordinated. Over time, the control point for these was consolidated into one building to deliver more effective control. This also allowed for the interlocking of signals, which is where a signalman cannot move certain levers in the lever frame which would display signals which conflict with each other, or with the direction of points on the track.
The standard signal cabin design is a two storey structure, which allows for an elevated view of the area under its control from the upper floor. The lower floor is used to accommodate the mechanics and interlocking of the lever frame and for storage. Most signal cabins are standalone structures but in some cases, they are integrated into the station building.