On 19/06/2019 19:43, Graeme Wall wrote:
On 19/06/2019 19:18, Basil Jet wrote:
On 19/06/2019 18:53, Graeme Wall wrote:
On 19/06/2019 18:02, Basil Jet wrote:
On 19/06/2019 14:03, Graeme Wall wrote:
On 19/06/2019 13:34, Recliner wrote:
On Wed, 19 Jun 2019 12:24:15 +0100, Roland Perry
wrote:

In message , at
12:04:50 on
Wed, 19 Jun 2019, Recliner remarked:

I pointed out that the buried/bridged
motorway will be built on a new alignment, to the west of the
current
M25, so building it won't disrupt the existing motorway or flights.
Only the short period of linking the old carriageways and new
diversion will cause any disruption, and that should be short
(mainly
a few days or weeks of lane closures, then a few hours of complete
closure while the traffic is switched to the new route).

It's far too close to the intersection with the M4 for the
geometry to
work. Not only that, Heathrow's own information shows the M25 route
undiverted (only local roads have new corridors):

https://aec.heathrowconsultation.com...tes/5/2019/06/

P1-11-Local-Roads-Diverted.jpg

Thanks for that. That map clearly confirms the M25 diversion to the
west: it has a more pronounced curve under the runways than the
current route. It's a small enough diversion not to need any changes
to the M4 junction.

I've overlaid a translucent Google Map view on top of the new map,
and
you can clearly see the diversion.

https://www.flickr.com/photos/recliner/48091808766/in/dateposted-friend/lightbox/



That confirms it is going to be foul of the current interchange
which is going to be less easy to adapt.

... although no bridges in either junction will have to be rebuilt.


If the new layout is foul of the current junction how is that going
to work?


Unless you have sight problems, you can work out everything I know
from the flickr image above.



I currently do have sight problems but that diagram clearly shows the
slip roads from the new alignment being foul of the existing layout. I'm
hoping to go and see the actual documents in the library tomorrow so may
get a better idea then.


The bridges are all in the centres of the junctions, and the roads in
those area are unchanged, unlike the roads on the southern part of the
M4 junction or the northern part of the T5 junction. (I'm not counting
gantries as bridges.)

--
Basil Jet recently enjoyed listening to
Prefab Sprout - 1985 - Steve McQueen