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.