North East Link

[Peter Freeman]

An existing TBM can be re-used in certain circumstances: https://www.herrenknecht.com/en/service ... hment.html

I was recently informed, reliably, that the four TBMs imminently to be launched for the Melbourne Metro (rail) project will be re-used soon afterwards. There's no definitive next project yet, but I can guess several candidates.

All four TBM's are now tunnelling for the Melbourne Metro. It appears most likely that they will be re-used for Melbourne's 'Suburban Rail Loop' project.
https://suburbanrailloop.vic.gov.au/

[Peter Freeman]

I'm not sure why the difference arises, but we'd do it [road tunneling] and you won't (and I'm not saying you should).

In part it's a question of whether you want to encourage more people to drive and whether your city could sustain that. London has a population density more than ten times that of Sydney ... * Sydney has ~400 people per square kilometre, ... a lower population density even than Los Angeles County, which is by anyone's standards sprawling and car-dependent.

So yes, you could make a case for building tunnelled motorways under London, like those built in Sydney, but ...

I don't think it's about the lack of will to dig tunnels; it's about how much motor traffic it's desirable to have in a city as old and as dense as London is.

Yes, all very true. But I'm not suggesting that London, or the UK generally, should build (many) NEW roads in tunnels. I do believe that it is the answer to some issues that currently seem to be in the too-hard basket.

A prime example is completing (or virtually completing) grade separation of the A406. This is not a decision "do I want to make a safe high capacity road around the north side of mid-suburban London". That decision was made about 70 years ago. The road's already there, and the job's almost done. I could be missing some detailed engineering snags, but Henly's Corner and Bounds Green both appear to have ample nearby space to make even cut-and-cover tunnelling feasible. Hardly any property acquisition, just temporary major ground disturbance. It's really not hard.

But I say once again - AU would, and does, but UK doesn't, and won't.

[Peter Freeman]

An existing TBM can be re-used in certain circumstances: https://www.herrenknecht.com/en/service ... hment.html

I was recently informed, reliably, that the four TBMs imminently to be launched for the Melbourne Metro (rail) project will be re-used soon afterwards. There's no definitive next project yet, but I can guess several candidates.

All four TBM's are now tunnelling for the Melbourne Metro. It appears most likely that they will be re-used for Melbourne's 'Suburban Rail Loop' project.
https://suburbanrailloop.vic.gov.au/

The four TBM's working on Melbourne Metro (rail) have just completed their work. Information in the official announcement was that there are plans to "re-purpose" them for another project. A fascinating footnote was that the "skins" will remain in the ground and form part of the permanent tunnel lining, with the insides being removed!

[Peter Freeman]

The N.E.L. main tunnelling contract is now under way, after a year or so of 'early works' spent shifting services, building a park-n-ride, etc. A consortium called 'Spark' will undertake the first and critical section that includes the tunnel. Their tender provided a design with significant improvements over the refence design, including increasing the tunnel length and decreasing the trenched-with-green-bridges length. TBM's are on order, the launch box is being piled, and tunnelling will commence in 2024. Completion date is 2028.
https://bigbuild.vic.gov.au/projects/no ... nk-program

[Peter Freeman]

The most detailed map that I've seen for final-form NEL is here -
https://bigbuild.vic.gov.au/projects/no ... unnels/map
(then scroll down to the map)

Only the under-construction tunnel section is included, not yet the associated M3 or M80 improvements. Also, it primarily shows ground-level works above the tunnel, including portals, but not the tunnel itself (there's not much to see down there). The image is highly zoomable - you can see the road-marking details.

[Truvelo]

The GSJ at the southern end looks really impressive, especially when comparing the existing M3 which will be twice as wide when complete. I wish we had as much enthusiasm for this sort of thing in urban areas as we had in the 60's.

[Peter Freeman]

The first TBM is on its way -
https://bigbuild.vic.gov.au/news/north- ... -sets-sail

[Peter Freeman]

Work on the next NEL section (Ring Road Completion) is now beginning -
https://bigbuild.vic.gov.au/library/nor ... ember-2023
https://bigbuild.vic.gov.au/__data/asse ... r-2023.pdf

Also kicking off is the upgrade to the middle part of Eastern Freeway -
https://bigbuild.vic.gov.au/news/north- ... ay-and-m80

The inner end and outer end of the Eastern Freeway will be the 4th and 5th (final) contracts. They will not begin for a couple of years yet.

[KeithW]

Yes, all very true. But I'm not suggesting that London, or the UK generally, should build (many) NEW roads in tunnels. I do believe that it is the answer to some issues that currently seem to be in the too-hard basket.

A prime example is completing (or virtually completing) grade separation of the A406. This is not a decision "do I want to make a safe high capacity road around the north side of mid-suburban London". That decision was made about 70 years ago. The road's already there, and the job's almost done. I could be missing some detailed engineering snags, but Henly's Corner and Bounds Green both appear to have ample nearby space to make even cut-and-cover tunnelling feasible. Hardly any property acquisition, just temporary major ground disturbance. It's really not hard.

But I say once again - AU would, and does, but UK doesn't, and won't.

More to the point TfL don't want it and they call the shots.

[Peter Freeman]

Five pre-loved roadheader machines have been transferred from Melbourne's Metro Tunnel (rail) project, where they've completed their work, to the North East Link project. They have begun digging the middle section of the M80 tunnels.

To explain, the NEL has three adjoining lengths of twin tunnel, each with a different construction method -

Northern 5km: Bored, with a cut-and-cover cavern halfway along, which the TBMs will have to cross. TBM parts have arrived at the portal site, and are soon to be assembled.
Middle 1km: SEM (sequential excavation method, formerly known as New Austrian Tunnelling Method). Started.
Southern 0.5km: Cut and Cover. Work has started on the Green Bridge that will house the portal and the southbound ventilation exhaust.

[Peter Freeman]

36 months in, the workforce and the rate of construction have gradually built up. Tunnelling is now occurring at pace on four large worksites, and about half of the project's surface length is also underway.

Here is the NEL's CEO providing a run-down of the current status -
https://www.youtube.com/watch?v=Qe98Vhg9qpg
Here's a flyover of the tunnelling sites, October 2023 -
https://www.youtube.com/watch?v=2czFLwJW3x4
and a more recent one -
https://www.youtube.com/watch?v=KkxpSl1hARo

Works on the M80 and M3 have just begun -
M80: https://www.youtube.com/watch?v=5vYSCPzmZfk
M3: https://www.youtube.com/watch?v=yRgSSvps_2A

I thought I knew about tunnelling, but this video taught me about Hydromills -
https://www.youtube.com/watch?v=mWOG8h-QsB0
If you let your seaches, or YouTube's algorithms, go wild, you'll find many technical explainers like that via NEL: TBMs, roadheaders, D-walls, bentonite usage and distribution, lining segment manufacture, super-load transports, gantry-crane driving, ...

The project completion date has slipped from 2027 to 2028, and the cost has increased from 16B$ to 26B$. However, there have been considerable design improvements along the way.

[Peter Freeman]

The first TBM, named 'Zelda', has begun operation from the northern end of the NEL tunnels. Its twin, 'Gillian', will follow in a few weeks (staggered twin tunnelling is normal). Progress will be about 10m/day. TBM retrievals will occur in 2026, project completion in 2028.

[Peter Freeman]

Of interest to extreme detail enthusiasts only (!) - documents relating to NEL.

A. The first two documents relate to the fairly short 'M80 Ring Road Completion' part of the project, from Plenty Road to the tunnel northern portals.

1. Landscape Design - this is a fairly clear view of the layout of lanes, ramps, etc.
https://bigbuild.vic.gov.au/__data/asse ... design.pdf

2. This one is probably more useful and comprehensible: 3D Visualisations (ie. artistic, but detailed and realistic, impressions).
https://bigbuild.vic.gov.au/__data/asse ... ations.pdf

B. Here are the corresponding two documents for the tunnel sub-project. This actually means the landscaping and road layouts on the surface above, and connecting to, the tunnels.

3. Landscape Design.
https://bigbuild.vic.gov.au/__data/asse ... Design.pdf

4. Visualisations.
https://bigbuild.vic.gov.au/__data/asse ... ations.pdf

C. And finally here are the corresponding two documents for the M3 upgrade between Burke Road and Tram Road - the part of M3 from which NEL branches off northwards. It shows the southern portal, and the larger of the two new Single Point Diamonds created by the project.

5. Landscape Design.
https://bigbuild.vic.gov.au/__data/asse ... Design.pdf

6. Visualisations.
https://bigbuild.vic.gov.au/__data/asse ... ations.pdf

Physical work on the M3 city (western) end, and M3 eastern part (where the interesting braiding will occur), has not started yet. Detailed layouts etc will be published in 2025.