In message , at 12:39:32 on Wed, 19 Jun
2019, Basil Jet remarked:
On 19/06/2019 12:21, Roland Perry wrote:
In message , at 07:53:25 on Wed, 19
Jun 2019, Recliner remarked:

They'll build the diverted, sunken, bridged M25 to the west of the
current road, with no disruption to road or air traffic during the
building, which might take a couple of years.

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, I don't think even an overnight closure is required. You
reduce it to one lane overnight while you repaint most of the
carriageway to have four (five?) lanes curving onto the altered
alignment. You stop the traffic for a minute while you "change the
points" and route the one traffic lane into a different coned alignment
over the already painted area. You then remove the earlier cone route
and finish painting the carriageway. Then put concrete barriers
guarding the abandoned route and remove all the cones. It's quite
common for the M25 to be down to one lane at night, and far preferable
to shutting it.

Don't give up the day job.

--
Roland Perry

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.

--
Graeme Wall
This account not read.

In message , at 12:31:49 on
Wed, 19 Jun 2019, Recliner remarked:

Are you talking about the earlier plan where the existing M4 M25
junction was half-removed and replaced by a weird junction further west?
The picture in the BBC article seems to be describing not that, but a
different plan where the M25 keeps its present horizontal alignment.

It's being moved slightly to the west, but not enough to change the M4
junction. You can see the curve to the new diverted alignment in one
of the images in these articles:

"Images released by the airport indicate that the M25, which widens to
12 lanes past Heathrow, would be rebuilt in a tunnel west of its
present route.

Two openings in the tunnel between the taxiways and runway would
improve stability, ventilation and visibility on the road."

https://www.thetimes.co.uk/article/h...over-m25-in-30
-year-expansion-f58v9f2ts?shareToken=3416809e5a92ad594cefa79d3391e 8a7

If anything, that shows the M25 bending slightly east, straightening the
existing alignment between J14 and J15.

https://www.thesun.co.uk/news/931931...pansion-reveal
ed-third-runway-finished-2026/

The map and artists impression there aren't even consistent (at the
granularity of the width of a 6+6 lane motorway).
--
Roland Perry

On Wed, 19 Jun 2019 14:03:37 +0100, 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.

Yes, it looks like there will have to be a small adjustment to the
northbound slip roads, but that should be relatively easy, as it will
make them straighter.

In message , at 12:43:48 on Wed, 19 Jun
2019, Clive D.W. Feather remarked:
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).

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

On 19/06/2019 14:29, Recliner wrote:
On Wed, 19 Jun 2019 14:03:37 +0100, 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.

Yes, it looks like there will have to be a small adjustment to the
northbound slip roads, but that should be relatively easy, as it will
make them straighter.


Except you have to take the change in levels into account which will
involve major construction works and you can't build the new sliproad
alongside and move the traffic over.

--
Graeme Wall
This account not read.

Graeme Wall wrote:
On 19/06/2019 14:29, Recliner wrote:
On Wed, 19 Jun 2019 14:03:37 +0100, 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.

Yes, it looks like there will have to be a small adjustment to the
northbound slip roads, but that should be relatively easy, as it will
make them straighter.


Except you have to take the change in levels into account which will
involve major construction works and you can't build the new sliproad
alongside and move the traffic over.


There won't be any change of levels where the new and old carriageways meet
— that'll be further south. But I agree that the connection stage will be
more complicated as it'll involve the slip roads as well as the main
carriageways.

I think what they might do would be to first move the northbound M25
traffic for the M4 on to the diversion so that it can then use the new slip
roads. The new through carriageway can then be extended over the old slip
roads to connect to the old through carriageway.

"Recliner" wrote in message
...
On Wed, 19 Jun 2019 10:57:29 +0100, "tim..."
wrote:



"Recliner" wrote in message
...
tim... wrote:


"Recliner" wrote in message
...
tim... wrote:


"Recliner" wrote in message
...
https://www.bbc.co.uk/news/business-48668001


well I don't know about the rest,

but I for one think that the idea that people who have little or no
business
at the airport are going to have to suffer 5 years of disruption
whilst
they
rebuild the M25 to create this Hub airport entirely unreasonable

Why do you think M25 users will suffer five years of disruption? It's
more
likely to be a few night time closures or lane restrictions.

they are going to put the whole road in a tunnel (presumably from the
way
it's described not by building a raft on top of it)

how can that not cause major disruption?


You've obviously not looked at the map,

what is "The Map" - I guess there is one, but no I didn't get to see it
(You
can blame that on my out of date browser if the original article included
a
link)

or read this thread.

as one of the first to reply, that would have been difficult

If you now read the thread, 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).

"Recliner" wrote in message
...
On Wed, 19 Jun 2019 10:57:29 +0100, "tim..."
wrote:



"Recliner" wrote in message
...
tim... wrote:


"Recliner" wrote in message
...
tim... wrote:


"Recliner" wrote in message
...
https://www.bbc.co.uk/news/business-48668001


well I don't know about the rest,

but I for one think that the idea that people who have little or no
business
at the airport are going to have to suffer 5 years of disruption
whilst
they
rebuild the M25 to create this Hub airport entirely unreasonable

Why do you think M25 users will suffer five years of disruption? It's
more
likely to be a few night time closures or lane restrictions.

they are going to put the whole road in a tunnel (presumably from the
way
it's described not by building a raft on top of it)

how can that not cause major disruption?


You've obviously not looked at the map,

what is "The Map" - I guess there is one, but no I didn't get to see it
(You
can blame that on my out of date browser if the original article included
a
link)

or read this thread.

as one of the first to reply, that would have been difficult

If you now read the thread, 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.

The plans that I can see show the new road so close that the idea that it
wont disrupt the current M25 is fiction.

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).

If you think that they can link a new route into a current motorways by only
diverting traffic for a few weeks then you have never seen how they do this

IME they narrow the road where the connection is to be made for the full
term of the works. They do this because they need access to the new road
for construction vehicles - how else are they going to build it?

tim

"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

tim