Gapped

A train stalled over a gap in the conductor rail of an electric railway is said to be "gapped". This occurs when the shoes on the train which collect the current have all lost contact with the current rail due to gaps left for junctions. Particularly prevalent at complex junctions such as the entrances to yards. See also conductor rail. A driver wh...
Found on http://www.railway-technical.com/newglos.shtml

Gapped

Getting "gapped" occurs when a train stops with all its shoes off the current rails and therefore without power to restart. Very embarrassing.
Found on http://www.trainweb.org/tubeprune/dictionary.htm
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