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One wonders how much of the actual station construction can take place in the 18-24 months before the TBMs turn up. You'd think they could do quite a lot in that time whilst leaving room to dismantle the TBMs upon their arrival.
One wonders how much of the actual station construction can take place in the 18-24 months before the TBMs turn up. You'd think they could do quite a lot in that time whilst leaving room to dismantle the TBMs upon their arrival.
From the press release "The machines will complete their journeys underground and the outer can of the machine will be left to form part of the tunnel. The mechanical components of the TBMs will be pulled back through the 4.5 mile tunnel and disassembled."
In another update for Northolt East for Nov 29 (only 4 days since the previous one):
Emily is at 3135m (+147m), Anne at 2840m (+120m).
These are better rates than before (36/30m/day respectively), suggesting maybe that the earlier positions were underestimated, as at Northolt West recently.
Emily would now appear to have passed under the River Brent, although the map graphics are missing for the two TBMs.
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.
One wonders how much of the actual station construction can take place in the 18-24 months before the TBMs turn up. You'd think they could do quite a lot in that time whilst leaving room to dismantle the TBMs upon their arrival.
At Euston? The station works haven’t been approved, so nothing will be built before they arrive. Besides they arrive a good mile north of the station, well out the way.
Less than 2 months into this design iteration but all the easy site preparation bits the nuclear industry does early on are largely in progress.
The utilites diversion should be nearly finished.
The sensible things they could do (that were already planned and paused):
Start removing soil and lowering the ground level across most of the site, could be done slowly so not noticeable change in traffic if going out by road
There are also the previously planned works to build a new P16 along the middle siding alignment to allow the current P16 area to be cleared.
Both would save few month when there is a plan.
The nominal Euston Station vs approaches to OOC site boundary is effectively at Hampstead Road and plenty is going on north of Hampstead Road productively.
Update on the Bromford TBMs (14 days Nov 25-Dec 9):
Mary Anne is at 4254m (+252m), Elizabeth at 2360m (+92m).
The former is now doing an impressive 14m/day.
This is another pair of TBMs to lose the large positional graphic on the location 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.
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Oddly, nothing this week from Northolt, where Shushila should be finishing its drive to Green Park Way about now.
Update on the Bromford TBMs (14 days Nov 25-Dec 9):
Mary Anne is at 4254m (+252m), Elizabeth at 2360m (+92m).
The former is now doing an impressive 14m/day.
This is another pair of TBMs to lose the large positional graphic on the location 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
Oddly, nothing this week from Northolt, where Shushila should be finishing its drive to Green Park Way about now.
Tunnel construction update We are writing to let you know that we expect Tunnel Boring Machine (TBM) Sushila to complete her tunnelling journey from West Ruislip to the Green Park Way Vent Shaft on 13 December. This milestone marks the completion of part of the tunnel construction of the new HS2...
www.hs2.org.uk
We are writing to let you know that we expect Tunnel Boring Machine (TBM) Sushila to complete her tunnelling journey from West Ruislip to the Green Park Way Vent Shaft on 13 December. This milestone marks the completion of part of the tunnel construction of the new HS2 line linking Euston to Birmingham. We expect TBM Caroline to reach the Green Park Way site in March 2025.
Well if it did, they are keeping quiet about it.
You'd expect a photoshoot for an event like this.
Maybe they are waiting for rail/HS2 minister Peter Hendy to be available.
Well if it did, they are keeping quiet about it.
You'd expect a photoshoot for an event like this.
Maybe they are waiting for rail/HS2 minister Peter Hendy to be available.
That's right. But I've read that before, without getting a clear picture of what they are doing. Here's another article, this time with diagrams! I find this makes it a lot clearer, though some things are still not clear. It's from Ground Engineering
Due to high groundwater levels, the TBMs will not have a “normal” breakthrough moment when they end their journeys.
Instead of breaking through the walls of the shafts, they will be received in steel reception chambers, or “cans”, at the bottom of the two shafts. These will ensure that the tunnel lining is fully sealed prior to removal of the TBMs. This is the first time this method has been used on HS2 and possibly in the UK.
“The steel can maintains this continuous connection to the exterior of the shaft, allowing sealing off of the exterior as the TBM breaks in,” says Hewett. “So that stops all the water, all that pressure from the water coming into the shaft. It creates a confined, sealed unit, to make it safe.”
One thing which is still not being made quite clear is that the lid goes on one end of the can and the TBM comes in from the other end. But as to what happens for the second TBM in that shaft - I guess it is enough that the can is now sealed against the shaft wall and tunnel at that end, but is it?
On second thoughts, that sounds wrong. For the first TBM, it could be sealed to the shaft at both ends. It's the second one that poses a problem, because now the far end leads to the tunnel, and needs to be sealed off.
Presumably, the can and lid would be reoriented 180degrees so that the second TBM enters the can and erects the lining to seal the second tunnel. This can be done because the first tunnel is sealed to the sealed-in shutter pipe before the lid is removed allowing the head TBM sections to be removed inside the can to be followed by the rest of it once the can is removed. Once that TBM is removed, the can is reassembled to receive the second TBM.
I don't think turning the can by 180 degrees is meaningful, as it has to be taken apart and the top part lifted out of the way for the extraction of the TBM sections.
I've re-read that second article, and it's becoming clearer. The cylinder of the can is made up of five rings, which are built on the surface. A tensioning cable is wrapped round each ring, to hold the segments together in the right shape so they seal. After all, you'd rather not be making a pressure vessel with pieces bolted together so they come apart easily!
These five rings are lowered into place, and pulled together to seal with each other and the TBM-side shutter pipe. Only then is the lid (end cap) lowered into the gap at the other end, and pushed against the can by jacks to make it seal. Now the can (which is filled with concrete for the TBM to bite into) has a continuous seal to the inside of the shaft. I still can't visualise the tunnel lining being sealed to the shaft around the incoming TBM, but it must be similar to normal tunnel lining operations.
Once that seal is made, the can can be taken apart, and the top part removed. After the TBM is out of the way, I think all the rest of the can's parts will be taken out too - to be checked over and reassembled as before. The second time the assembly will seal to the other shutter pipe, and the lid go on the other end. So the effect is the same as turning it around.
The other picture in the Ground Engineering article, looking down the shaft, may help with visualising this:
Given that the can will be filled with concrete and that the TBM will enter it off-centre, I doubt that the tunnelling team would be removing all of this from overhead for fear of accidents. I suspect that they’ll take the cutter head up to the can cap then disconnect it and reverse the remainder clear of the can. The cap can be removed then the entire can lifted out for refurbishment followed by driving the TBM forward for dismantling and removal.
Northolt East TBMs were updated today (for 14 days Nov 29-Dec 13):
Emily is at 3366m (+231m) and Anne is at 3069m (+219m), both representing good progress at 15/16m/day.
They have both passed the Westgate Vent Shaft and the River Brent, and are now adjacent to the Alperton Lane Industrial Area.
But still nothing since November 27 from Northolt West, where from separate reports Shushila should have finished its run by now.
All TBMs will shut down for an extended Christmas and New Year break shortly.
EDIT Dec 19:
Northolt West was updated today.
Shushila is reported at 8007m (+51m) and Caroline at 6675m (+450m).
Shushila is shown as having -7m to go to complete - presumably it is being manoeuvred near the Green Park Way shaft.
Still no official word of the completion of Shushila's 8km bore.
Caroline is moving well at 20m/day, so a completion date in March looks likely (1095m to go).
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
Progress updates are now likely to be paused until after TBM work restarts in early January.
The giant Tunnel Boring Machine (TBM), named Sushila, reached the Green Park Way vent shaft in Ealing yesterday [19th December 2024] breaking through into a reception can filled with foam concrete.
The innovative method has been adopted due to high water pressure in the ground on the site. It allows the TBM to maintain its pressure while sealant can be applied from the tunnel lining to prevent water ingress.
Once the reception can is depressurised, it will be opened and the TBM will be lifted out.
The PR piece mentions a rate of 16m per day, but in fact Shushila averaged just shy of 10m/day over its 8km drive which took 805 days.
That compares to the actual rates of 16m/day achieved by the two Chiltern TBMs over their 16km drives which took close to 1000 days.
Both Northolt West TBMs were stopped for periods, to be reconfigured after surface sink-holes appeared near the Ruislip portal, and in general boring rates were lower than those at Chiltern.
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A final pre-Christmas update for Northolt East appeared today for Dec 20 (7 days from Dec 13):
Emily is at 3369m (+3m), and Anne is at 3145m (86m).
So Emily is essentially stopped, while Anne continues at around 12m/day.
HS2 is an extraordinary feat of modern design and civil engineering, standing apart as the biggest infrastructure project in Britain. This project update provides a snapshot of the huge progress we’re making as we prepare to launch the operational railway in the early 2030s, using new methods of...
My apologies if it was covered upthread, but is it known when tunnelling recommences after the extended Christmas shutdown?
Also, has there been any indication of how long they think it will take to remove Sushila from the ‘can’/vent shaft?
I should think all the TBMs will start up tomorrow, like most big construction sites in the UK.
The extraction process for Shushila and its backup train looked to be quite complicated.
They probably have a couple of months before Caroline arrives on the scene.
The first updates of the new year show that the TBMs have just restarted after the 2-week holiday break.
At Northolt East (24 days Dec 20-Jan 13):
Emily is at 3380m (+11m), Anne at 3255m (+110m).
So not up to full production yet after the break.
Anne is only 125m behind Emily.
At Northolt West (21 days Dec 19-Jan 9):
Caroline is at 6675m (+0m) - ie has not moved.
Shushila completed its drive on Dec 20.
EDIT:
In an update today from Bromford (37 days Dec 9-Jan 15):
Mary Ann is at 4496m (+244m), Elizabeth is at 2550m (+190m).
Taking 2 weeks out for Christmas gives daily rates of around 8-10m/day.
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
EDIT 2:
Northolt East TBMs were updated after only 4 days (Jan 13-17).
Emily is now at 3396m (+15m), and Anne is at 3317m (+62m).
As a result, Anne, making faster progress, is only 79m behind Emily.
The graphics representing the TBM locations on the HS2 site map are all over the place at low resolution, hopefully the positions are accurate.
More progress at Northolt East (10 days Jan 17-27):
Emily is at 3579m (+184m), Anne at 3378m (+61m).
So progress has reversed, with Emily moving well while Anne goes slow.
Both TBMs are close to Alperton Lane, Emily having crossed below.
More progress at Northolt East (10 days Jan 17-27):
Emily is at 3579m (+184m), Anne at 3378m (+61m).
So progress has reversed, with Emily moving well while Anne goes slow.
Both TBMs are close to Alperton Lane, Emily having crossed below.
Both HS2 media releases on Euston TBMs (2nd and 10th December) just say tunnel boring will commence in 2025. So date is vague.
In practice there is likelihood of a TBM team transferring from another one when that completes, so a few days after another TBM finishes might be a good guess.
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Bromford tunnel TBMs have been updated too on 27th Jan
Mary Ann 4580m, 1020m to go
Elizabeth 2740m, 2860m to go
So both Mary Ann and Caroline have just of a kilometre to bore.
Both HS2 media releases on Euston TBMs (2nd and 10th December) just say tunnel boring will commence in 2025. So date is vague.
In practice there is likelihood of a TBM team transferring from another one when that completes, so a few days after another TBM finishes might be a good guess.
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Previous statements and indications have been June-July 2025 for the "Euston" start.
Originally all 6 London main bore TBMs would have been in action at only but now realistically 4 or 3-->3.5 max in practice.
In relativity the Euston Tunnelling effectively has 2 phases:
1. Get the TBMs out and sufficiently clear of the station box so the don't get in the way of the station construction more than the barest minimum, and this probably needs to be before the end of the year
2. The main tunnelling phase (ignoring a very slow carefully finish), ideally finishing before mid/end 2027.
A) The key thing is to get both Euston TBMs clear of the OOC box so before full funding as agreed it could just have been one team doing both. The reality is that the northern machine will have to move first for logistics reasons.
B) The segment contract is the same as Northholt East hence progressing the Euston bore may come at the cost of slower progress on the Northholt East bores.
C) The transporters and other ancillary equipment is unlikely to available for a while after the other bores complete e.g. personnel transporters needed for some dismantling or as the tunnel bores get longer additional transporters could help as the journey times increase.
D) likely completion of other bores (ignoring TBM extraction for the moment which will slow things down)
i) Caroline 66 days at current pace e.g. ~Easter
ii) Emily 120 day at mid term average pace so end of May at the earliest
iii) Anne 120 day at mid term average pace so mid-late of June at the earliest
E) dismantling and removing each TBM is very likely to take more time than that availbel before the next TBM arrives hence they will all slow down and have to wait - which needs fewer shifts staffed and uses less segments which might make some staff and materials available for the Euston TBMs with out affecting Northolt TBM completion. Are the complete TBMs being lifted out at Greenford or just the heads with the tails driven out (i.e. reversed) which would need so TBMs staff too.
F) it looks like shifts on the 4 Northolt TBMs were never fully staffed with one always progressing more slowly (which may indicate fewer shifts staffed) or stopped for maintenance of issue resolution. If well planed it reduces spend in a month etc. (keeping DfT and treasury happy) but ultimately probably costs more as construction goes on for longer.
Hence Euston TBM are likely to see a slow start if they do start in summer.
As others said, TBM crews will most likely move from other TBMs to the Euston ones.
One Northolt TBM has already finished so some crew is already released, or should be soon if they still have some tasks to perform, the next TBM should finish in 3 months or so so we'll get another crew available.
We don't have to worry about dismantling TBMs as it will be done by different teams, it shouldn't hold crew availability for the Euston TBMs. I think the main holding issue is preparation of the TBMs themselves and all the support infrastructure like conveyor belts etc.
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