The tram tunnel underneath Kingsway once took passengers from Holborn to Waterloo Bridge, providing a link between the north and south London tram networks.
Well, not quite!
But, despite the implication of the piece above about BAM and their chums' Grout, trams never crossed Waterloo Bridge; but entered the tunnel north of Holborn and reappeared under Waterloo Bridge on the Embankment. A potted history of the line now follows:-
1942-1945 Waterloo Bridge rebuilding
Herewith a script extract.