On Jan 25, 9:32 pm, Steve M wrote:
It's not a loop as such... IIRC, terminating trains tip out at Euston,
cross over to the other line, and then onto the bit of track which links
the Northern with the Piccadilly Line. Driver changes ends (clear of
Northbound trains) and returns into service at Euston NB when a suitable
gap arises.

You've got it _completely_ backwards - there's no tipping-out required
at all.

A driver at King's Cross n/b makes an announcement, then proceeds
towards signal J10, which has a lit No.4 feather. The train will
proceed straight ahead into the original C&SLR n/b tunnel, bypassing
the 1960s tunnel built to divert the n/b Northern to make space for
the Victoria Line tunnels. This tunnel leads to the original scissors
crossover cavern south of Euston, where the train uses a facing
crossover to switch to the s/b line and pull into the s/b platform at
Euston, where he stops and changes ends.

http://www.trainweb.org/tubeprune/Eu...0KX-leu5-4.gif refers.