HS2 TBM Progress

[swt_passenger]

Why they never planned a spur for the already present and unused, extra station platforms at Heathrow baffles me.
It’s literally been future proofed to provide extra train capacity, it seems daft to deny passengers from Birmingham and beyond a more simple journey to Heathrow. No one wants to lug bags over a rail network with so many changes… classic oversight I think!

Although they did originally have a plan for a spur to Heathrow, and you can still see on the relevant online drawings the intended position of the two junctions, they’re effectively at either end of the Colne Valley viaduct:

https://assets.publishing.service.gov.uk/media/5a815f3340f0b62305b8e982/C222-ATK-CV-DPP-020-000001-FPD.pdf

https://assets.publishing.service.g...7f59fcecd0/C221-MMD-CV-DPP-010-203700-FPD.pdf

IIRC it wouldn‘t have ever gone via T5 spare platforms though, they were already reserved for other routes such as western and southern links. Probably off-topic for a discussion of tunnelling progress, as it’s the tunnel that will never be built now…

 

[PLY2AYS]

Although they did originally have a plan for a spur to Heathrow, and you can still see on the relevant online drawings the intended position of the two junctions, they’re effectively at either end of the Colne Valley viaduct:

https://assets.publishing.service.gov.uk/media/5a815f3340f0b62305b8e982/C222-ATK-CV-DPP-020-000001-FPD.pdf

https://assets.publishing.service.g...7f59fcecd0/C221-MMD-CV-DPP-010-203700-FPD.pdf

IIRC it wouldn‘t have ever gone via T5 spare platforms though, they were already reserved for other routes such as western and southern links. Probably off-topic for a discussion of tunnelling progress, as it’s the tunnel that will never be built now…

Thanks for the information! I’ll have a gander.
Hadn’t realised that about Colne Valley junctions.

Apologies for going off track.

 

[Bald Rick]

Why they never planned a spur for the already present and unused, extra station platforms at Heathrow baffles me.
It’s literally been future proofed to provide extra train capacity, it seems daft to deny passengers from Birmingham and beyond a more simple journey to Heathrow. No one wants to lug bags over a rail network with so many changes… classic oversight I think!

The ‘spare‘ platforms at T5 were nover intended for HS2 and not compatible anyway. They are reserved for Southern / Western link.

 

[LNW-GW Joint]

HS2 has a piece on the completion of the west portal (the Birmingham end) of Bromford tunnel, ready for the arrival of the two TBMs in 1-2 years' time.
It feeds into a 750m cut and cover tunnel* which has now started construction.
So there's not going to be much scenery on the stretch out of Curzon St, until the Delta Junction area.

HS2 completes Bromford Tunnel portal at Washwood Heath

Huge excavation operation of 22 metre deep tunnel portal prepares the gateway for high speed trains into Birmingham The first 1,600 tonne tunnelling machine will break through the portal wall later this year View and download photos here, B-roll drone video here, Depot and Control Centre CGIs here

mediacentre.hs2.org.uk

* this is essentially the length of the adjacent Washwood Heath rolling stock depot

You can see the portal taking shape on Google Maps (photo probably several months old) in this screenshot.
The Washwood Heath site is the brown zone to the lower left, and the portal now completed is the white hatched recatngle in the north-east of this zone.
It's right next to the M6, A47 and the Derby main line.

 

[Bald Rick]

So there's not going to be much scenery on the stretch out of Curzon St, until the Delta Junction area.

It’s east Birmingham. There is no scenery. Being below ground will be a blessing.

(disclaimer - I used to live there).

 

[snowball]

Does the M6 viaduct have piled foundations where the tunnel will go under it? (near Wanderer's Walk I think.) How deep is the tunnel there?

 

[SCDR_WMR]

It’s east Birmingham. There is no scenery. Being below ground will be a blessing.

(disclaimer - I used to live there).

Agreed. Tunnel all the way from delta to Curzon!

 

[LNW-GW Joint]

Updates today May 15 for four TBMs at Bromford and Northolt West.
At Bromford (16 days from Apr 29): Mary Ann is at 2280m (+132m), Elizabeth at 120m (+0m).
At Northolt West (12 days from May 3): Shushila is at 4995m (+92m), Caroline at 4772m (+212m).

So a good spell for Caroline (17m/day), half of that for Mary Ann and Shushila, and Elizabeth seems to be stopped for the moment.
Mary Ann has made a crossing below the River Tame and is now under industrial sites until it reaches the intermediate vent shaft in about 500m.
The Northolt pair now have residential housing either side of their route under the wide ex-GWR formation.

Edit May 20:
The Northolt East TBMs were updated today (10 days from May 10):
Emily is at 520m (+78m), Anne at 189m (+90m).
So steady progress from both, around 8-9m/day.

 

[Snow1964]

Updates on TBMs

Sushila (Northolt west) 92m in 12 days to May 16th (63.51%) 5000m
Caroline (Northolt west) 212m in 12 days to May 16th (60.87%) 4770m

Mary Ann (Bromford) 132m in 15 days to May 15th (40.71%) 2280m
Elizabeth (Bromford) (launched 1 May) 120m (2.19%) 120m

Emily (Northolt east) 78m in 10 days to May 21st. (9.45%) 520m
Anne (Northolt east) 90m in 10 days to May 21st (3.45%) 189m

 

[LNW-GW Joint]

Updates today (May 29) for the four Northolt TBMs (14 days since May 15):

Northolt West:
Shushila 5302m (+307m), Caroline (4928m (+156m)

Northolt East:
Emily 590m (+70m), Anne 285m (+96m)

So very good progress at the west end, still modest if steady progress at the east end.
Another 2 weeks should see Shushila beneath Northolt LU station.

 

[absolutelymilk]

Updates today (May 29) for the four Northolt TBMs (14 days since May 15):

Northolt West:
Shushila 5302m (+307m), Caroline (4928m (+156m)

Northolt East:
Emily 590m (+70m), Anne 285m (+96m)

So very good progress at the west end, still modest if steady progress at the east end.
Another 2 weeks should see Shushila beneath Northolt LU station.

With 216 days left of 2024 and 2,538m left to go, it's looking increasingly possible Shushila will be finished before Christmas! (if there are no more major stoppages...)

 

[LNW-GW Joint]

With 216 days left of 2024 and 2,538m left to go, it's looking increasingly possible Shushila will be finished before Christmas! (if there are no more major stoppages...)

I'm not sure finishing by Christmas was ever on for the pair launched at West Ruislip.
Maybe in the next quarter (winter 2025).
Both should have finished before the crews are needed for the Euston tunnels (assuming the funding comes through for that).
Mary Ann at Bromford is also going slowly (compared to the Chiltern pair), and might finish by mid-2025.
The next "completion" might well be the Colne Valley viaduct, now on its last water crossing to the south pier.
But progress is hard to judge - drone pictures should tell us.

 

[absolutelymilk]

What's the reason that the Northolt TBMs seem to be making slower progress than the Chiltern TBMs? Roughly 10m/day on average compared to 19m/day for the Chilterns. Is it ground conditions or something else?

 

[LNW-GW Joint]

What's the reason that the Northolt TBMs seem to be making slower progress than the Chiltern TBMs? Roughly 10m/day on average compared to 19m/day for the Chilterns. Is it ground conditions or something else?

Part of it will certainly be ground conditions.
The Chiltern tunnels were largely driven through chalk, much like the Channel Tunnel, which seems easier than the London clay either side of OOC.
The TBMs that started at West Ruislip had a difficult early stage, with some well-publicised sink-holes on the surface which led to a redesign of the cutter heads.
They are also regularly close to residential property and there is a system of test boreholes in advance of the TBMs which analyse the ground conditions.
While the Northolt TBMs are largely beneath the GWR/LU route, they are only 50m or so from residential properties either side so will be taking things carefully.
The West pair (Shushila/Caroline) do seem to have improved their progress rate lately, which is a good sign, but the recently-launched East pair (Emily and Anne) have still to find their feet.
The Bromford pair (Mary Ann and Elizabeth) are generally working below the River Tame (as well as being beneath the M6 at times), which may well have uncertain geology. At least they are further away from residential property for most of the tunnel length.

 

[LNW-GW Joint]

First update for 3 weeks from Bromford (May 15-June 7):
Mary Ann is at 2422m (+142m), Elizabeth still at 120m (+0m).

So modest progress for Mary Ann (6m/day), but Elizabeth hasn't moved for 6 weeks.

An update also from Northolt East (9 days May 29-June 7):
Emily is at 754m (+164m), Anne at 484m (+199m).

Much better progress here, at 18-22m/day.

 

[JKF]

The ‘spare‘ platforms at T5 were nover intended for HS2 and not compatible anyway. They are reserved for Southern / Western link.

Drifting off topic, but would there not be benefit in continuing southern link trains up to OOC if/when it is ever built? Good for connectivity and also a bit of extra capacity between Heathrow and OOC.

 

[Benjwri]

Drifting off topic, but would there not be benefit in continuing southern link trains up to OOC if/when it is ever built? Good for connectivity and also a bit of extra capacity between Heathrow and OOC.

Extra platforms at Heathrow would not help. The capacity issues are between Airport Junction and OOC

 

[LNW-GW Joint]

The Northolt West TBMs were updated on June 12 (14 days from May 29):
Shushila is at 5473m (+171m), Caroline at 5019m (+91m).

So modest progress, but both are now past the 5km mark out of their 7.8km drives.
Shushila is just about level with the west end of the Northolt LU station platforms.
Another month should see it reach the Mandeville Road vent shaft, the second of the two on its route to Greenford Way.

Edit:
Northolt East TBMs updated on June 17 (10 days from June 7):
Emily is at 891m (+137m), Anne at 578m (+94m), so steady progress.
Both TMs are below the GW/LU route alongside Western Avenue.

Edit 2:
Northolt East TBMs updated again, for 7 days June 17-24:
Emily is at 972m (+81m), Anne at 675m (+97m).
Good progress of 12-14m/day.

Good progress also at Bromford, in the first update for a while (June 7-25):
Mary Ann is at 2538m (+116m), Elizabeth at 286m (+166m).
Elizabeth has finally moved from the 120m point it sat on for at least 6 weeks.

Meanwhile, a great leap forward at Northolt West (12-25 June):
Shushila is at 5814m (+321m), Caroline at 5270m (+251m).
These are rates of 19-26m/day.
That puts Shushila past Northolt LU station and about level with Mandeville Road vent shaft - maybe it will pause there for a bit.
Caroline is now past Eastcote Lane bridge.

So we are unusually up to date with all the TBMs, as shown in this graphic:

In your area map - HS2

Search our interactive In Your Area Map to find information about current or planned HS2 construction works taking place across the route.

www.hs2.org.uk

It's noticeable the HS2 Ltd has not put out any media stories (apart from the appointment of the new CEO, Mark Wild) since the general election was called.
I expect they will be happy to stay out of the limelight for a while.

 

[BRX]

There are a number of bored tunnel segment plants around the country, some remote such as Isle of Grain, Hartlepool and Avonmouth, and some at more adjacent sites eg Denham, for the Chiltern tunnels and Kingsbury in Warwickshire. I think the latter will be nearest Bromford. It would be interesting to see a map showing all the locations across the country, and which sites they feed.

There are also the different types of concrete precast units used in the green tunnels which are cut and cover. I think they come from Stanton in Derbyshire.

The segments from Grain are transported by rail. For most of the year this happens in darkness but I've managed to film them a couple of times in reasonable light due to the long days at this time of year. The trains run from Grain to West Ruislip, pretty much daily. They are pictured here running through south London.

 

[LNW-GW Joint]

Nice pictures. Looks like about 180 segments per train.
I think it's 7 segments to a ring of tunnel, so that would make about 25 rings.
At something like 1.5m of tunnel length per ring, that would make about 37.5m of tunnel.
The Northolt West TBMs are doing quite well at typically 15-20m per day, so one of those trains just about matches a day's tunnelling by the two TBMs.
No doubt there are stockpiles of segments at each end of the train route as well.

The concreting plant at Hyde which produced the segments for the Chiltern tunnels will have finished its main job.
The adjacent plant which is producing the much larger segments for the Colne Valley viaduct will be reaching the end of its job in the next few months.
The concreting plants can then be dismantled and the area reconfigured for the eventual railway.

 

[BRX]

No doubt there are stockpiles of segments at each end of the train route as well.

Yes, you can see them all stacked up (alongside what I assume is the reception siding) at West Ruislip if you go past on the Chiltern main line.

Obviously there must be quite a feat of organisation going on behind the scenes! For example they must all have to be stacked such that you don't need to get at the one at the bottom of a pile before you've used the ones above it.

 

[LNW-GW Joint]

More solid progress at Northolt East, where the updates now seem to be weekly.
For 7 days June 24-July 1:
Emily is at 1058m (+86m), Anne at 761m (also +86m).
So both doing a steady 12m/day.

Edit July 9:
Two more updates to record:
Northolt East updated on July 5, only 4 days after the update above:
Emily is at 1156m (+98m), and Anne at 850m (+89m).
Both of these represent fast progress of 22-24m/day.

Bromford updated today for 14 days up to July 9:
Mary Ann is at 2694m (+156m), Elizabeth at 410m (+124m).
Continuing the lower rate of 9-11m/day which seems typical of this tunnel section.
Mary Ann must now be very close to the Bromford intermediate shaft at Orton Way.
It is about 100m short of the half-way point in its drive, after 11 months work.

 

[Geogregor]

Green Park Way Vent Shaft:

https://www.newcivilengineer.com/la...don-tbm-extraction-and-vent-shaft-12-07-2024/

There are four TBMs that will arrive at this shaft: two coming from West Ruislip, boring the 8km Northolt Tunnel West, and two coming from the Victoria Road Crossover Box boring the 5.5km Northolt Tunnel East.

The complex design of the 45m deep shaft involves a purpose-built can to provide a watertight environment when the TBMs eventually arrive for withdrawal.

They will perform some very complex engineering there:

The steel can in the shaft, manufactured in Sheffield, will provide a steel reception chamber to ensure the tunnel is fully sealed prior to the removal of each TBM. It has been built in parts and shipped down to the London site.

The cradle for the can is installed first to the bottom of the shaft. This will provide a stable foundation for the steel can.

Then the steel can lid will be installed and welded to the rim of the tunnel to guarantee water tightness.

According to schematics made by SCS for HS2, the limited space at the site and availability of cranes means the can will need to be installed in limited segments, lowered on to the cradle and then bolted together.

When all the can segments are in place, the steel can lid will be pished back against the can with a hydraulic jack system where maximum movement of 0.1m is expected.

After relevant supports have been removed, the can will be filled with a “suitable fill” and undergo a pressure test. If that test is successful, it will be depressurised before the first TBM arrives.

The TBMs will make their way towards the site and as they approach will extend hydraulic arms to the steel can lid. The reception chamber will then be opened and the machines will be lifted out. HS2 and SCS JV representatives could not confirm the precise method for TBM extraction because of the complexity of the operation.

The complexity had led HS2 and SCS JV to create digital rehearsals in 4D where renderings of the TBMs, the tunnels and the shafts are pictured moving through time.

All four TBMs will arrive at the shaft during 2025.

 

[LNW-GW Joint]

I think that's the first we've seen of progress on the Greenford Way shaft, and is evidently well advanced.
Based on current positions and rate of progress, the leading Northolt West TBM (Shushila) boring the western (Birmingham-bound) tunnel from West Ruislip might reach the Greenford Way shaft by about year-end.
Shushila has currently completed almost 75% of its bore (6km out of 8km) and has just 2km to go to reach the shaft.

Another statistic is that the total Northolt bored tunnel complex of 27km (2x13.5km, Old Oak-West Ruislip) is expected to pass the 50% complete stage this month.
That's with the 4 TBMs chewing away at a combined rate of about 60m a day.

Edit July 18:
Here's the HS2 announcement of the half-way point in the Northolt tunnel being reached.

We’re half way there! HS2’s Northolt Tunnel under the capital is 50% complete

Quartet of tunnelling machines boring the Northolt Tunnel between West Ruislip and Old Oak Common station have built half of the tunnel New video and images shows the unstoppable momentum of the HS2 programme in London

mediacentre.hs2.org.uk

HS2’s tunnelling team are celebrating completing half of the 8.4-mile twin bored Northolt Tunnel underneath London.
Four tunnel boring machines (TBM) are being used the complete the tunnel that will carry high-speed trains between HS2’s super-hub station at Old Oak Common, west London, and the outskirts of the capital at West Ruislip.
The machines will excavate 16.8 miles of tunnel overall – two bores over the 8.4-mile length – making it the second longest tunnel on the new railway after one recently excavated beneath the Chiltern Hills.

The first machine, named Sushila after a local teacher, was launched eastwards from West Ruislip in October 2022. This was followed one month later by TBM Caroline, named after astrologer Caroline Herschel, which is used to excavate the adjacent tunnel.

I have to quibble with the description of Caroline Herschel, after whom TBM Caroline is named, as an "astrologer".
She was a fully fledged astronomer in her own right, and was the sister of William Herschel who discovered the planet Uranus (from Bath).
Caroline made a real contribution to astronomical science and discovered several comets.
That means she was a proper scientist, and was not involved in the mumbo jumbo of astrology.
Rant over.

 

[Geogregor]

50% of tunneling completed at Northolt Tunnels:

We’re half way there! HS2’s Northolt Tunnel under the capital is 50% complete

Quartet of tunnelling machines boring the Northolt Tunnel between West Ruislip and Old Oak Common station have built half of the tunnel New video and images shows the unstoppable momentum of the HS2 programme in London

mediacentre.hs2.org.uk

Very comprehensive video, showing all the vent shafts progress:

 

[AeM]

I think that's the first we've seen of progress on the Greenford Way shaft, and is evidently well advanced.
Based on current positions and rate of progress, the leading Northolt West TBM (Shushila) boring the western (Birmingham-bound) tunnel from West Ruislip might reach the Greenford Way shaft by about year-end.
Shushila has currently completed almost 75% of its bore (6km out of 8km) and has just 2km to go to reach the shaft.

Another statistic is that the total Northolt bored tunnel complex of 27km (2x13.5km, Old Oak-West Ruislip) is expected to pass the 50% complete stage this month.
That's with the 4 TBMs chewing away at a combined rate of about 60m a day.

Edit July 18:
Here's the HS2 announcement of the half-way point in the Northolt tunnel being reached.

We’re half way there! HS2’s Northolt Tunnel under the capital is 50% complete

Quartet of tunnelling machines boring the Northolt Tunnel between West Ruislip and Old Oak Common station have built half of the tunnel New video and images shows the unstoppable momentum of the HS2 programme in London

mediacentre.hs2.org.uk

I have to quibble with the description of Caroline Herschel, after whom TBM Caroline is named, as an "astrologer".
She was a fully fledged astronomer in her own right, and was the sister of William Herschel who discovered the planet Uranus (from Bath).
Caroline made a real contribution to astronomical science and discovered several comets.
That means she was a proper scientist, and was not involved in the mumbo jumbo of astrology.
Rant over.

Harrumph indeed!! Seconded!

 

[LNW-GW Joint]

An update on the Northolt TBMs was posted today, for the 17 days July 5-22.

Northolt West: Shushila is at 5822m (+8m), Caroline at 5691m (+421m)
Northolt East: Emily is at 1156m (+0m), Anne at 933m (+83m).

So Shushila is essentially stopped at the Mandeville Road vent shaft and is probably having maintenance there before its final 2km push to Greenford Way.
Caroline is still making good progress (15m/day) in the adjacent bore, and is now only 130m behind Shushila, alongside Northolt LU station.
Emily has not moved in those 17 days, and Anne is only moving slowly (5m/day).
The metrics confirm the overall Northolt tunnel excavation is now past the half-way point.

Edit:
Bromford TBMs also updated today, 13 days July 9-22:
Mary Ann is at 2816m (+122m), Elizabeth at 656m (+246m).
Steady progress.
Mary Ann is now past the half-way point in its drive, and must be right by the Orton Way vent shaft.

 

[GRALISTAIR]

Wow that is pretty good steady progress for Caroline. Good news.

 

[LNW-GW Joint]

Before the political excitement today, HS2 Ltd updated the Northolt East TBM positions for the week 22-29 July:
Emily is at 1348m (+192m) and Anne is at 1116m (+183m).
Both these are about the best rates so far for these TBMs (26m/27m/day).

Edit Aug 2:
Keen to share their good progress at Northolt East, HS2 Ltd shows (for 4 days July 29-Aug 2):
Emily is at 1451m (+103m), Anne at 1190m (+74m).
Emily in particular is moving at 25m/day.
Emily is also now pretty much clear of residential areas for the next 1km or so to Hangar Lane.

Edit Aug 6:
HS2 Ltd has updated the data for Bromford, for 14 days to Aug 6:
Mary Ann is at 2980m (+164m), Elizabeth at 922m (+266m).
More good progress, particularly for Elizabeth (17m/day).

Phase 1 tunnelling (exc Euston) now has less than 20km to go, of the original 73km.

 

[LNW-GW Joint]

Updates today for all four Northolt TBMs.

Northolt West (21 days to Aug 12):
Shushila 6337m (+515m), Caroline 5841m (+150m).

Northolt East (7 days to Aug 9):
Emily 1559m (+108m), Anne 1190m (+0m).

So Shushila looks to be moving quickly (24m/day) after negotiating the Mandeville Road vent shaft, while Caroline seems to have reached the shaft.
Emily is moving well (15m/day), but Anne is stopped for some reason.