The locking is transmitted from the Interlocking FrameAn alternative term for Lever Frame. (or equivalent) to the
Signalling FunctionA Signal, set of Points or other part of the train control system. to be released by means of a key. It can be applied to
Ground FrameA control point containing levers or switches to permit the local operation of Points in Running Lines, Sidings and, where provided, the associated Signals. Thi... pointsItems of permanent way which may be aligned to one of two positions, Normal or Reverse, according to the direction of train movement required. or level crossings.