In message , John Rowland
writes
Hi all,

The picture in page 2 of
http://www.murphygroup.co.uk/pdf/Tunnelling/Elstree.pdf seems to show that
there is (or was) a single track railway in the new National Grid tunnel
from Elstree to St Johns Wood, underneath the A5. Despite having almost half
the cross-sectional area of a Jubilee Line Extension tunnel, the whole 20
kilometres of it seems to have been built for the cost of 200 metres of
double-track JLE! (An unfair comparison for several reasons...)

Unfair comparison because JLE wasn't built by Murphy's erm... imported
workforce? ;-)

--
Bob Adams