HS2 TBM Progress

[Snow1964]

HS2 has announced today that Long Itchington tunnel (where TBM Dorothy finished couple of years ago) has reached construction milestone with vital elements, including three cross passages, concrete finishing works and base slabs, and emergency and maintenance walkways, all complete.

Now just needs fit out for railway.

• HS2 has unveiled the first twin-bore tunnel on the project to be completed at Long Itchington Wood in Warwickshire.
• The development sees the completion of features such as cross passages, base slabs and walkways – ahead of the internal fit-out of railway systems which will allow high-speed trains to operate.
• View and embed new HS2 video:
• View and download photos: https://mediacentre.hs2.org.uk/reso...nnel-2/long-itchington-wood-tunnel-completion

HS2 marks major construction milestone at Long Itchington Wood Tunnel

HS2 has unveiled the first twin-bore tunnel on the project to be completed at Long Itchington Wood in Warwickshire. The development sees the completion of features such as cross passages, base slabs and walkways – ahead of the internal fit-out of railway systems which will allow high-speed...

mediacentre.hs2.org.uk

 

[absolutelymilk]

Should we be worried that it took a couple of years to complete the civils for a relatively short tunnel? Hopefully the other tunnels will be done more rapidly...

 

[stuu]

Should we be worried that it took a couple of years to complete the civils for a relatively short tunnel? Hopefully the other tunnels will be done more rapidly...

No. No point throwing resources at something which isn't urgent. A sensible decision, for once

 

[LNW-GW Joint]

No. No point throwing resources at something which isn't urgent. A sensible decision, for once

A probably pertinent point is when will the completed Long Itchington tunnel, or any other section, be fitted out with rail systems?
That could still be several years away, with the purchase contracts only signed in November 2024 and with no detailed delivery plan made known.

Also Long Itchington tunnels are short relative to the others, and I got the impression the 38 cross-passages for the Chiltern tunnels were being constructed close behind the TBMs.
There's also the progress on the various headhouses and vent shafts to consider in the longer tunnels, not needed at Long Itchington.

.

 

[mythnormadman]

A probably pertinent point is when will the completed Long Itchington tunnel, or any other section, be fitted out with rail systems?
That could still be several years away, with the purchase contracts only signed in November 2024 and with no detailed delivery plan made known.

Also Long Itchington tunnels are short relative to the others, and I got the impression the 38 cross-passages for the Chiltern tunnels were being constructed close behind the TBMs.
There's also the progress on the various headhouses and vent shafts to consider in the longer tunnels, not needed at Long Itchington.

.

23 of 34 Northolt cross passages have been completed based on HS2 documents. So moving quickly behind the TBMs

 

[Snow1964]

Bromford TBMs update

Mary Ann 4888m on 24 Feb with 712m remaining
Elizabeth 3058m on 24 Feb with 2542m remaining

 

[absolutelymilk]

Bromford TBMs update

Mary Ann 4888m on 24 Feb with 712m remaining
Elizabeth 3058m on 24 Feb with 2542m remaining

LNW-GW Joint beat you to it! (although by editing post 510 so it's not particularly obvious)

 

[Snow1964]

Also Long Itchington tunnels are short relative to the others, and I got the impression the 38 cross-passages for the Chiltern tunnels were being constructed close behind the TBMs.
There's also the progress on the various headhouses and vent shafts to consider in the longer tunnels, not needed at Long Itchington.

MPD Construction Group recently won contract to install 32km of walkways in Northolt tunnels using Bridgeform system, with work starting in May, taking nearly a year

MPD Construction Group has landed a pivotal contract for HS2 to install 32 kilometers of concrete walkway in the Northolt Tunnel. Utilizing their innovative Bridgeform system—developed with KERN Tunneltechnik—this fully automated, hydraulically operated formwork solution promises efficient execution.

Work starts in May, with MPD set to deliver 60,000 cubic meters of concrete, employing a peak workforce of 125. This collaboration enhances their longstanding partnership with HS2, which began in 2019. Managing Director Liam McManus emphasized three key objectives: safety, quality, and certainty. The Bridgeform system meets these crucial demands while ensuring unrestricted emergency access between tunnels.

The nearly year-long investment in this project marks a major step forward for tunnel construction efficiency. This highlights the importance of innovation in infrastructure projects. How can further automation transform construction?

Bimconnectdaily on Instagram: "MPD Construction Group has landed a pivotal contract for HS2 to install 32 kilometers of concrete walkway in the Northolt Tunnel. Utilizing their innovative Bridgeform system—developed with KERN Tunneltechnik—this full

1 likes, 0 comments - bimconnectdaily on February 26, 2025: "MPD Construction Group has landed a pivotal contract for HS2 to install 32 kilometers of concrete walkway in the Northolt Tunnel. Utilizing their innovative Bridgeform system—developed with KERN Tunneltechnik—this fully automated...

www.instagram.com

 

[absolutelymilk]

Northolt East TBMs update
Anne 4092m (+238m compared to 14 Feb) on 28 Feb with 1408m remaining
Emily 4197m (+257m) on 28 Feb with 1352m remaining

More excellent progress!

 

[LNW-GW Joint]

Northolt East TBMs update
Anne 4092m (+238m compared to 14 Feb) on 28 Feb with 1408m remaining
Elizabeth 4197m (+257m) on 28 Feb with 1352m remaining
More excellent progress!

I think you mean Emily rather than Elizabeth (which is at Bromford).
But good progress.

 

[hwl]

I think you mean Emily rather than Elizabeth (which is at Bromford).
But good progress.

Both nominally completing in mid May at the current pace which is impossible due to the dismantling procedure so the last bit will be very slow and sporadic.
Caroline should probably finish around Easter based on the last update at the end of Jan.

 

[Snow1964]

Update from HS2 on West Ruislip portal area March-July 2025

Tunnelling from West Ruislip to Greenford will be completed by March 2025, and works are underway to remove tunnelling support structures inside and outside the tunnels. The demobilisation and removal works will be carried out for the following:
• The conveyor structure
• The launch chamber entrance
• Rail siding
• Gantry cranes and segment yard
• Conveyor bridges

Update on ongoing 24/7 demobilisation works at West Ruislip Portal site

We wrote to you in November to inform you about works at our site at West Ruislip Portal. We would like to update you on the works programme as the demobilisation progresses throughout the next few months until 31 July 2026. The next phase of the demobilisation and removal works will be carried...

www.hs2.org.uk

A full set of dates for the various parts on the above list are listed on the following pdf (there is also some local map of affected areas.

https://assets.hs2.org.uk/wp-content/uploads/2025/03/FINAL-AWN-West-Ruislip-Portal-site-demob-works-update-Feb-2025.pdf

 

[LNW-GW Joint]

We haven't seen a position for TBM Caroline since January 27, but it could now be close to completion.
The rail delivery of segments to West Ruislip for Caroline appears to have completed, and the equipment which supported Shushila in the western tunnel can obviously be removed.
It's good to see a major work site being evolved into its final state, with local disturbance coming to an end.

== Doublepost prevention - post automatically merged: 10 Mar 2025 ==


Edit Mar 10:
Northolt East made its usual weekly update today, for March 7 (7 days from Feb 28):
Emily is now at 4322m (+125m), Anne at 4154m (+62m).
Emily is past Bideford Avenue and about 150m short of Perivale station platforms, with 1227m of its drive left.
Anne may be slowing to avoid reaching the Greenford Way shaft too soon.

Edit Mar 11:
Bromford TBMs were updated today, for March 10 (14 days from Feb 24):
Mary Ann is at 5010m (+122m), Elizabeth at 3058m (+0m).
So Mary Ann continues its steady advance, with just 590m to go.
Elizabeth has stopped for these 2 weeks, and is 2km behind Mary Ann.

There's just Caroline at Northolt West to update now, last update January 27.

 

[Palmerston]

Encouraging to see a lot of the tunnelling getting close to completion.

 

[Geogregor]

Massive gantry at Greenford shaft which will be used for the removal of the TBMs:

 

[LNW-GW Joint]

TBM Shushila was extracted from the Greenford Way vent shaft on March 15, after completing its 8km Northolt West tunnel drive from West Ruislip.
Shushila completed its drive in the western tunnel on January 9, so 10 weeks to dismantle the system and complete the lift out.
Three more TBMs will follow the process at Greenford Way later this year, the next very likely to be Caroline in the eastern tunnel around June.

IN PICTURES: Spectacular images of the removal of HS2’s huge tunnelling machine following its 5-mile journey

Following its 5-mile drive underneath the capital, HS2 lifted Tunnel Boring Machine (TBM) ‘Sushila’ out of the ground at the Green Park Way site in Greenford, West London.

mediacentre.hs2.org.uk

The positions of the working TBMs have temporarily vanished from the HS2 Ltd graphic:

Interactive route map

Use HS2’s interactive map to explore the entire route of Britain’s new high-speed railway. Find present and upcoming works, tunnels, station locations and community updates — all in one easy-to-navigate map.

www.hs2.org.uk

 

[Snow1964]

It appears extended working hours will be taking place at Chipping Warden Green tunnel. 1st April-31 Oct 7am- Midnight Mon-Fri and 7am-6pm weekends

https://assets.hs2.org.uk/wp-content/uploads/2025/03/Notice-of-extended-hours-working-Chipping-Warden-March-2025.pdf

Similar extended hours at Greatworth green tunnel

https://assets.hs2.org.uk/wp-content/uploads/2025/03/Notice-of-extended-hours-working-Greatworth-March-2025.pdf

Not clear if this was planned ages ago, or if tunnels are running late and this is to speed up construction.

 

[LNW-GW Joint]

The TBMs have reappeared on the HS2 web site graphic, showing new positions for March 15 at Northolt East (8 days from March 7):

Emily is at 4463m (+141m), Anne at 4154m (+0m).
So Emily forges ahead at 17m/day, while Anne is stopped.
Emily is essentially under the south end of the Perivale LU station platform.

 

[chris2]

Presumably they're stacking up to come out at Greenford one at a time?? Or could one from each direction arrive simultaneously? Which will be next to come out?

 

[absolutelymilk]

Presumably they're stacking up to come out at Greenford one at a time?? Or could one from each direction arrive simultaneously? Which will be next to come out?

Emily (Northolt east) and Caroline (Northolt west) are at roughly the same reported distance to go (just over 1k) as per their last update, but Emily's position was updated on 15 March, whereas Caroline hasn't been updated since 27 January so could be finishing in the next few days

 

[chris2]

Emily (Northolt east) and Caroline (Northolt west) are at roughly the same reported distance to go (just over 1k) as per their last update, but Emily's position was updated on 15 March, whereas Caroline hasn't been updated since 27 January so could be finishing in the next few days

Ah interesting, didn't spot that - so could be that Caroline is next to come out then. What happens to the rest of the machine, does it get lifted out as well or pulled back through to the launch site?

 

[Snow1964]

Presumably they're stacking up to come out at Greenford one at a time?? Or could one from each direction arrive simultaneously? Which will be next to come out?

There are 2 holes (one for each tunnel) and gantry crane straddles both. So could be setting bits up while a lift is in other side.

However 2 TBMs arrive from opposite directions in each tunnel (4 in total), but second one will need first one removed before it can move forward to extraction shaft.

 

[DavidGrain]

TBM Shushila was extracted from the Greenford Way vent shaft on March 15, after completing its 8km Northolt West tunnel drive from West Ruislip.
Shushila completed its drive in the western tunnel on January 9, so 10 weeks to dismantle the system and complete the lift out.
Three more TBMs will follow the process at Greenford Way later this year, the next very likely to be Caroline in the eastern tunnel around June.

IN PICTURES: Spectacular images of the removal of HS2’s huge tunnelling machine following its 5-mile journey

Following its 5-mile drive underneath the capital, HS2 lifted Tunnel Boring Machine (TBM) ‘Sushila’ out of the ground at the Green Park Way site in Greenford, West London.

mediacentre.hs2.org.uk

The positions of the working TBMs have temporarily vanished from the HS2 Ltd graphic:

Interactive route map

Use HS2’s interactive map to explore the entire route of Britain’s new high-speed railway. Find present and upcoming works, tunnels, station locations and community updates — all in one easy-to-navigate map.

www.hs2.org.uk

I am interested in why the TBMs are being lifted out vertically. If they have reached the far end of the tunnel, should they not come to the surface of their own accord?

 

[TheDavibob]

I am interested in why the TBMs are being lifted out vertically. If they have reached the far end of the tunnel, should they not come to the surface of their own accord?

Is it not just that the Ruislip <-> Old Oak Common tunnel is very long, and is therefore being bored from both ends with the TBMs meeting in the middle (and therefore needing to be lifted out)?

 

[mr_jrt]

IIRC, the ground conditions on either end differ dramatically, so having different TBMs designed more appropriately for said ground conditions made sense. The overall distance was a bit of a secondary factor.

 

[jfowkes]

I am interested in why the TBMs are being lifted out vertically. If they have reached the far end of the tunnel, should they not come to the surface of their own accord?

Is it not just that the Ruislip <-> Old Oak Common tunnel is very long, and is therefore being bored from both ends with the TBMs meeting in the middle (and therefore needing to be lifted out)?

Basically yes, they need to be lifted out because they're in the middle of the tunnel. But note that even if there has been a single drive from one end to the other, they'd still need to be lifted in/out at the Old Oak Common end as Victoria Box and the station are below ground level

 

[LNW-GW Joint]

I am interested in why the TBMs are being lifted out vertically. If they have reached the far end of the tunnel, should they not come to the surface of their own accord?

Northolt tunnel (13.5km in total from OOC to West Ruislip) is being bult in two halves, of 8km and 5.5km, meeting below ground at Greenford Way, where they will be extracted via the vent shaft.
The western section started at ground level at West Ruislip, and one of the two TBMs has now been extracted at Greenford Way.
The second western TBM will follow soon, and then the two eastern TBMs.

The Chiltern tunnel (16km) was built in one go, and the two TBMs started and finished at ground level at the tunnel portals.
The same was true for the short Long Itchington tunnel (1.6km, now complete), and is also the case for the 5.5km Bromford tunnel approaching Birmingham.
For the 7.2km Euston tunnels, the two TBMs are being lowered below ground at OOC, and will emerge at ground level near Euston.
Most of the TBM assemblies will be drawn back through the constructed tunnel to the starting point, leaving just the outsize cutting head to be lifted out.

Occasionally, there is no financial case to remove a TBM from below ground, as was the case for the TBMs boring the central section of the Channel Tunnel, which were diverted off-line and left in the chalk in mid-channel at the end of their job.
I think one of the Crossrail TBMs suffered the same fate under east London.

 

[DavidGrain]

Thank you to all of you who have replied to my question about the TBMs being lifted out vertically. Very interested and informative.

 

[LNW-GW Joint]

HS2 has updated the position of TBM Caroline at Northolt West today, covering over 7 weeks since January 27.
On March 19 it was at 7882m, +932m over 51 days or 18.2m/day.
It has only 118m to go to the finish at Greenford Way, so breakthrough in about 10 days seems possible.

 

[Snow1964]

HS2 has updated progress of Emily (digging Northolt tunnel East)
20 March 4.46km +141m in 12 days. (so about 1.1km to go)