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Old June 19th 19, 09:07 PM posted to uk.transport.london
Recliner[_3_] Recliner[_3_] is offline
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Default Latest Heathrow master plan

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.