A form of locking whereby the full travel of the lever is inhibited until the
operation of the function (for example pointsItems of permanent way which may be aligned to one of two positions, Normal or Reverse, according to the direction of train movement required. More) is complete and detectionThe proof of the position of the Points (Normal or Reverse) to the Interlocking equipment. More is
obtained. The levers function is achieved when the full travel of the lever is
reached (for example, NBD-R lock). See also BacklockingPrevention of completion of a lever stroke to the fully normal position until the conditions required by the interlocking are satisfied. See also Check Locking ... More and
Checklocking.