On Wed, 26 May 2010 04:56:23 -0700 (PDT)
lonelytraveller wrote:
As for the loop at mount pleasant, its a comparatively small thing to
dig a new bypass around the loop than it is to dig an entirely new
route across the whole of london. Besides, mount pleasant /
clerkenwell / essex market could do with a tube station, the met and
thameslink lines run through it but don't stop.

I would imagine that by the time you've stripped out all the tracks, cables
and tunnel lining so you can enlarge it you've probably spent more time and
money than you would if you just bored a new tunnel. Tunnels arn't dug with
picks and shovels any more - a TBM won't care if it has to dig the whole
tunnel itself or theres a small tunnel already there , it will take more or
less the same time. The only difference will be in the amount of spoil
needing to be carried away. Plus why inflict a windy route on a new
rail line when for high speed it needs to be as straight as possible.

B2003