On Tue, 9 Oct 2007, John Rowland wrote:

Tom Anderson wrote:

Cannon Street bridge is 7.1 metres above the high water level of the
Thames [1], perhaps less at the ends. The rail deck will be a little
above that - not more than 9 metres, and probably less. It's about 260
metres from the point where the bridge makes landfall to Cannon Street
itself, where the space occupied by the station ends (ish). If you
hollowed out the existing station and put in a downward-sloping track
at a gradient of 1:30 (generally considered the practical maximum, i
think), you could drop 8.5 metres in that distance, leaving you at
about the level of the river. You need about four metres over the top
of the track for the train (six if you want OHLE, which we don't). If
Cannon Street is four metres or more above the level of the river, this
idea is just about plausible - at least this far!

In terms of getting to Moorgate, you're then alright, as you have about
650 metres to run, in which space you can dive another 20 metres, which
i think is enough.

You would need to have flat platforms under Walbrook, to replace Cannon
Street Station.

Either there or further north. If the station was part of the Bank
complex, you might need to add another exit somewhere.

tom

--
It is a laborious madness, and an impoverishing one, the madness of
composing vast books. -- Jorge Luis Borges