cross-passage

From cross- +‎ passage.

cross-passage (plural cross-passages)

1. An underground passage between two parallel tunnels, provided for use in the event of an emergency.
   • 2023 December 13, “Network News: HS2 makes good progress on emergency cross-passages... and continues tunnelling from Old Oak Common to Euston”, in RAIL, number 998, page 10:

     The smaller cross-passages between the two running tunnels are for use in emergencies. Unlike the main tunnels being excavated by Tunnel Boring Machines (TBMs) Florence and Cecilia, they are dug using remotely controlled mini-excavators.

2. An underground passage between two underground station platforms.