# Finsbury Park (southbound Piccadilly line), Highbury & Islington
(northbound WAGN), Euston (northbound Northern Line, City branch) -
tracks diverted in the 60s to give cross-platform interchange with
the
new Victoria Line, with the old course just about visible at each
end
of the diversions. (Similar tunnels also visible on the Northern
Line
near Angel, London Bridge and Borough, albeit for somewhat
different
reasons.)

And at Stockwell, didn't the Northern Line swap a track with the
Victoria Line to enable cross-platform interchanges?


No, the Northern remained in the same place - the Victoria Line just came
up either side of it.

The remnants of the siding/access to depot at Stockwell are still visible
through the train window on the SB Northern Line approach - unless you
blink, then you'll miss them :-)


Roger