In message ,
Colin Rosenstiel writes

However, if they had, would it have allowed access for reversal without
considerable new construction? I am more surprised in retrospect that no
running connection between the Piccadilly and Victoria lines was put in
which would have been trivially simple.

There is a connection both east/northbound and west/southbound between
the Picc and Victoria lines for engineers trains. As the signalling
systems are so different from each other (the Victoria is automatic), it
would not be possible to run 73 stock on the Vic. or 67 stock on the
Picc. other than under a total possession.
--
Steve Fitzgerald has now left the building.
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