From Wiktionary, the free dictionary

interlocking (comparative more interlocking, superlative most interlocking)

1. Linked, locked, or fitted closely together.

   All societies have three key interlocking elements: Religion, economics, and politics.

interlocking (plural interlockings)

1. (rail transport) An arrangement of signal apparatus that prevents conflicting movements through a set of intersecting tracks, such as junctions or crossings.

   • 1955 April, R. H. Warring, “Some Early Railway Signals”, in Railway Magazine, page 233:

     There was still no attempt to arrange interlocking between points and signals; that came later. In 1856, John Saxby carried out the principle involved in interlocking—the prevention of signals and points being in conflicting positions—and erected apparatus to do that at this same junction.

   • 1961 March, “Talking of trains: Collision at Waterloo”, in Trains Illustrated, page 138:

     In addition to the usual interlocking between conflicting signal and point levers achieved by electric locks, track circuits, when occupied, hold signals governing entry to the relevant line at danger; [...] The up main through inner home signal was held at danger by interlocking, because the track circuits of a conflicting route ahead of it were occupied by another train [...].

interlocking

1. present participle and gerund of interlock

• interlocking on Wikipedia.Wikipedia