On 19 July, 17:12, Paul Terry wrote:
In message . li, Tom
Anderson writes

I don't see any reason that the line couldn't go via Vauxhall, with the
southbound tunnel leaving the loop much further clockwise, and the
northbound tunnel bending west rather than east. Both tunnels could run
under what i assume is a gasworks.

It's possible that the developers are aware of the enormous difficulties
in building the Victoria Line through Vauxhall. There's a pocket of
water-bearing gravel and unstable clay around the station (plus the
Effra River, many ancient sewers, and the Thames flowing only yards
away).

The station had to be built within a coffer-dam supported by deep piles,
and the escalator shaft required extensive freezing of the surrounding
ground before it could be bored.

I suspect that nobody building a relative cheap extension to the
Northern line would want to go through all that again.
--
Paul Terry

I heard that they were originally planning to take the Waterloo & City
line to Battersea, via Lambeth High Street, but Boris nixed it as the
area around Lambeth High Street is basically just run down council
estates, and (ignoring the fact that a station would kick start
redevelopment, of what would be a very desirable area if it was tidied
up, as its zone 1 and so very very close to central london - just
opposite parliament in fact) he didn't want criminal types, of the
sort he imagines fills these estates, taking the opportunity to turn
up at Battersea and loiter, buggering up the development's chances.

But if they did that, it would be easy to get the line to vauxhall,
and they could go over the effra (by shallow cut + cover) or do the
sloane square thing, instead of worrying about how to go under it.