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.

--
Basil Jet recently enjoyed listening to
Nine Horses - 2005 - Snow Borne Sorrow

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?

--
Graeme Wall
This account not read.

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.


--
Basil Jet recently enjoyed listening to
Nine Horses - 2005 - Snow Borne Sorrow

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.

--
Graeme Wall
This account not read.

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

In message , at 20:09:11 on Wed, 19 Jun
2019, Basil Jet remarked:
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.)

Talking of gantries; along with lamp-posts, central reservation
barriers, and all the other street furniture, they'd have to be removed
along the affected stretches to make the "set of points, with road cones
swapping the flow overnight" operation postulated up-thread.
--
Roland Perry

On 19/06/2019 20:09, Basil Jet wrote:
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.)


What about the sliproads?

--
Graeme Wall
This account not read.

In article , Roland Perry
writes
Presumably all the rerouting of traffic on the A14 project is going
swimmingly, to a similar plan?

All the bits I've seen have been.

For example, the new temporary northwestbound entry slip at Bar Hill was
done that way. There's lots of bits of new carriageway waiting to be
connected (e.g. northwestbound between the services north of Bar Hill
and the Swavesey intersection, though I think that's waiting for the
Lolworth bridge to be completed).

Or, for another example, the diversion of the westbound A14 loop on to
the M11 (or possibly temporarily-not-M11). Or the diversion of the
northwestbound A1307 between Girton and the new Dry Drayton roundabout.

--
Clive D.W. Feather

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?


You first connect the completed new carriageway and its M4 slip road to the
old slip road just before it splits into the east and west bound links. For
the next few months, traffic heading for the M4 will be diverted to the new
northbound carriageway, while through traffic will continue to use the
existing carriageway. During this time, the new carriageway will be built
through the old northbound slip road to connect to the ood carriageway.
Again, there will be and closures for a few weeks and an overnight complete
closure as the final connection is made.

Southbound is easier, but, again, connecting traffic from the M4 might
continue to use the old carriageway for a little while after the through
M25 traffic has been diverted to the new carriageway.

tim... wrote:


"Recliner" wrote in message
...
On Wed, 19 Jun 2019 12:43:48 +0100, "Clive D.W. Feather"
wrote:

In article , Roland Perry
writes
The only disruption will come at the end, when the traffic is diverted
to
the new route. My guess is that the northbound traffic will be moved
first,
with a few weeks of lane 1 closures required while they connect the new
to
the old carriageways, then an overnight closure for the final switch to
be
made. The same procedure would then be followed a few months later to
divert the southbound carriageway to the new alignment.

The amount of work you would be expecting them to do "overnight" beggars
belief.

I disagree.

Build the two new carriageways. At each end, cut them off very close to
the edge of northbound lane 1 (there's no hard shoulder, right? if there
is, adjust description accordingly).

Cone off northbound lane 1. Spend a week or two filling in the narrow
gap between the old and new northbounds at each end.

Not sure that you even need a closure to switch over. Simply move all
the cones.

Repeat for the southbound (though this time you're closing lane 4).


Yes, that's what I'm expecting.

I have never in my life seen construction companies do this

even when the new road is well away from the old route

It costs millions extra to do it that way

Why would it cost any extra? You have a completely segregated work site to
the west of the existing road, to build the new, lowered carriageways, with
runway and taxiway bridges. This might take 2-3 years, and won't affect the
existing motorway, except for a few lane closures while a safety wall is
built between the existing northbound carriageway and the work site.

When the new carriageway is ready, you need to close lane 1 of the old
northbound carriageway for a few weeks while the physical connection of the
road surfaces is made, and then an overnight closure for first the M4-bound
traffic to be diverted, and then again when the through traffic is
switched. A few months later, a similar process is used to connect the
southbound.

It won't be nearly as disruptive as when the M25 was widened to 12 lanes in
the area.