"Matt Wheeler" wrote in message
...

"John B" wrote in message
oups.com...
Marratxi wrote:
Why would it require any at all? Surely it could just bridge
it?
That would be the cause of the disruptive alterations. It's
generally
frowned upon to build a new bridge over an operating motorway...
They did it with CTRL and the QE2 bridge so why not elsewhere ?

In case I wasn't clear above, I meant "over a motorway without
closing
the motorway for the duration of the bridge-building".

Except the QE2 bridge doesn't go over a motorway... and the CTRL runs
under the bridge, not over it.
I'm not sure if the CTRL is over the road or before the tunnel mouth
(going north bound on A282.


Obviously you
can build a bridge over a motorway, but you can't do it without
disrupting traffic, which is what the original "why would it require
any at all" question was about.

--
The new CTRL line goes over what is essentially the northbound M25 as it
emerges from the Dartford tunnel and under the southbound lane, which is on
the QE2 bridge. As the CTRL website puts it "The new railway passes beneath
the QEII Bridge approach spans ('threading the needle') and over the exit
from the Dartford Tunnel, before running alongside the Purfleet By-pass and
the existing railway through Rainham to Dagenham" it also mentions "West of
Ashford the new railway crosses the M20 and follows the motorway corridor to
Detling in the Boxley valley north of Maidstone." I believe these bridges
were constructed to the side of the roads in question and then slid into
position with comparatively little disruption of the motorways.
Cheerz,
Baz