On Sun, 01 Jan 2012 21:12:10 -0000, Terry Casey
wrote:

In article ,
says...

On Sun, 01 Jan 2012 18:30:22 -0000, dennis@home
wrote:



Its cheaper to bore one tunnel these days.


How much would it cost to bore, says, one mile of dual tunnel capable of
carrying two tracks, and how much for one tunnel large enough for both
tracks? Make any assumption you like about the specification of the
trains
- e.g. Circle line standard.

The Circle is an Underground (sub surface) line - mainly cut and cover.

The deep tubes are bored.

You can take a tube train on the underground but you can't take an
underground train down the tube ...


But I did offer him the choice of any size - Central line if he wishes. Or
Glasgow's orange worms.

--
Rod