HS2 TBM Progress

[absolutelymilk]

None of the TBMs have updated on my map, and Emily has 1,086m to go, not 1.6k

 

[LNW-GW Joint]

More TBM updates yesterday:

Northolt East (6 days Mar 15-21):
Emily 4574m (+111m), Anne 4379m (+225m).
As Anne has suddenly jumped roughly double its usual distance after being stopped for a week, perhaps last week's update was missed.
They are both averaging 18m/day and are rapidly closing the gap to Greenford Way, with Emily now alongside Perivale LU station.

Bromford (14 days Mar 10-24):
Mary Ann is at 5174m (+164m), Elizabeth at 3146m (+88m).
Elizabeth is on the move again after a week's stoppage.
Mary Ann has just 426m left to do, although rates are still about half that at Northolt.

 

[Snow1964]

I would have thought, if they are planning a media breakthrough event it is likely to be Mary Ann at Bromford. Makes for better PR to have bored a whole tunnel and breaking through into the 2 track cutting than a TBM stopping in an extraction shaft in mid tunnel at Greenford.

 

[Palmerston]

Northolt West tunnels are now both complete.

Second HS2 tunnelling machine completes 5-mile drive under the capital

TBM Caroline has arrived at Green Park Way in Ealing, the second TBM in London to complete this year HS2's Northolt tunnel is now 93% complete

mediacentre.hs2.org.uk

 

[GRALISTAIR]

Northolt West tunnels are now both complete.

Second HS2 tunnelling machine completes 5-mile drive under the capital

TBM Caroline has arrived at Green Park Way in Ealing, the second TBM in London to complete this year HS2's Northolt tunnel is now 93% complete

mediacentre.hs2.org.uk

Another great milestone. Good to see.

 

[Snow1964]

HS2 has also released a video, about Northolt tunnels, following Caroline's completion including some info on Ruislip portals with acoustic pores. Also mentions 10 of 34 cross passages (at 500m intervals) now finished

== Doublepost prevention - post automatically merged: 3 Apr 2025 ==



per tunnel tracker

Emily (Northolt East) 4.74km on 3rd April, +168m in 8 days
other TBMs not updated

 

[mythnormadman]

HS2 has also released a video, about Northolt tunnels, following Caroline's completion including some info on Ruislip portals with acoustic pores. Also mentions 10 of 34 cross passages (at 500m intervals) now finished

== Doublepost prevention - post automatically merged: 3 Apr 2025 ==



per tunnel tracker

Emily (Northolt East) 4.74km on 3rd April, +168m in 8 days
other TBMs not updated

Interesting, back in February they wrote in an update "Twelve cross passages have been completed on the NTW and 7 completed on the NTE. There are 12 remaining CP to be built across both tunnel phases."
Of those 12, five had been allocated slots for their completion.

 

[LNW-GW Joint]

Emily had 807m to go on Mar 28, which is 5 weeks at the rate of the last week (24m/day).
Anne is reported at 4496m (+117m) on Mar 28.
The position graphics on the progress map for the live TBMs were missing for several days recently.

 

[absolutelymilk]

per tunnel tracker

Emily (Northolt East) 4.74km on 3rd April, +168m in 8 days
other TBMs not updated

The "In your area" map produced by HS2 themselves shows it as 4.74km as of 28 March, not 3 April - wonder if 3 April is the date that Tunnel Tracker spotted the change?

Also, by my calculations there is less than 5k of tunnelling in total left to go

 

[TBMEngineer]

We are expecting the Downline TBM to be at GPW in a month and a half, all going well. Roughly 400 rings left until GPW. However there is now a change in geology, from pure London clay to a mix of silty sand and clay, so could be slower progress.


Upline TBM is not far behind with roughly 600 rings left.

See below image

 

[LNW-GW Joint]

The progress graphic on the HS2 web site has been updated for Northolt East, but it doesn't quite match the obviously genuine data shown by TBMEngineer above.
Firstly the date given is April 4 (7 days from Mar28), and secondly the data for TBM Anne is different.
Emily is shown at 4771m (+29m), Anne at 4582m (+86m).
Progress has slowed from recently, but as noted above the ground conditions are changing as the finish line approaches.

In your area map

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

 

[absolutelymilk]

The progress graphic on the HS2 web site has been updated for Northolt East, but it doesn't quite match the obviously genuine data shown by TBMEngineer above.
Firstly the date given is April 4 (7 days from Mar28), and secondly the data for TBM Anne is different.
Emily is shown at 4771m (+29m), Anne at 4582m (+86m).
Progress has slowed from recently, but as noted above the ground conditions are changing as the finish line approaches.

In your area map

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

I think the readings could both be true *if* Emily had been stopped between the two readings (4 April vs 5 April), and Anne had covered 22m, which is possible if the reading from the map had been made earlier in the day compared to the reading from TBMEngineer (taken at 17:40)

 

[TBMEngineer]

I think the readings could both be true *if* Emily had been stopped between the two readings (4 April vs 5 April), and Anne had covered 22m, which is possible if the reading from the map had been made earlier in the day compared to the reading from TBMEngineer (taken at 17:40)

Downline has been stopped for the past weeek or so for some maintenance and repairs.

The Upline was stopped for a few days and then restarted.

Downline will continue to plow ahead at roughly 30m a day, whilst the Upline will come to a maintenance stop at Easter time.

 

[absolutelymilk]

30m a day is good going!

 

[LNW-GW Joint]

Downline = Emily (western tunnel of the pair, Birmingham bound).
Upline = Anne (eastern tunnel, OOC/Euston-bound).

 

[TBMEngineer]

Downline = Emily (western tunnel of the pair, Birmingham bound).
Upline = Anne (eastern tunnel, OOC/Euston-bound).

Apologies yes ha we only call them Downline and Upline

== Doublepost prevention - post automatically merged: 8 Apr 2025 ==

30m a day is good going!

There’s scope for faster but not required.
We could definitely go 45m per 24 hours. Depends on ground and machine breakdowns - other factors etc

 

[absolutelymilk]

Bromford TBMs both updated, with another roughly 200m done since the last update 14 days ago. Mary Anne should be done in another 14 days if it it keeps up this pace!

 

[Snow1964]

Bromford TBMs both updated, with another roughly 200m done since the last update 14 days ago. Mary Anne should be done in another 14 days if it it keeps up this pace!

Mary Ann showing as 5382m on April 7th with 218m to go
So late April breakthrough seems likely

Probably worth reminding everyone that the Washwood Heath portal structure is a 750m long deep trench which has already been dug, there are some pictures of it (nearly year ago) on this link. At the time HS2 suggested Mary Ann would complete end of 2024

Bromford Tunnel

www.hs2.org.uk

 

[GRALISTAIR]

Apologies yes ha we only call them Downline and Upline

== Doublepost prevention - post automatically merged: 8 Apr 2025 ==


There’s scope for faster but not required.
We could definitely go 45m per 24 hours. Depends on ground and machine breakdowns - other factors etc

Wow- that is good.

 

[Snow1964]

New update on HS2 Chiltern tunnel.

The TBMs finished months ago, but they have now completed the southern portal, which is up to 220m long with holes to dissipate pressure waves and avoid sonic booms.

Some pictures are on the link, although last photo seems to show a gap between the portal and bored section not yet built.

Contractors building HS2 have completed work on a pair of innovative extensions to the southern portal of its longest tunnel to eliminate the possibility of ‘sonic boom’ being created by high-speed trains entering at 200mph.

The structures, built at the southern end of the railway's 10-mile Chiltern Tunnel to the north-west of London, are near identical to those now under construction at its northern portal in Buckinghamshire.

All trains entering tunnels anywhere in the world force air forward, creating pulses of energy that roll along the tunnel causing a small release of air pressure into the outside world at the far end. Known scientifically as ‘micro pressure waves’, they are inaudible on conventional railways. But in high-speed rail tunnels, air shoved forward without escape routes can create powerful pressure waves that emerge as an audible ‘thud’ or ‘sonic boom’.

In a first for the UK rail network, HS2’s design includes extensions on all eight tunnels where trains enter at speeds above 140mph. However, the length, physical setting and aesthetic of those at each end of the line’s tunnel beneath the Chiltern Hills mark them out as unique even to HS2.

HS2 Ltd chief engineer, Mark Howard explains,

“The maximum speed of HS2 varies along the route. But where the train is entering a tunnel travelling above 140mph we are building portal extensions to prevent ‘sonic boom’ occurring. Although there are several tunnels on the line where train speed will be higher than in the Chiltern Tunnel, no other combines speeds of 200mph with length of 10 miles. Its these unique physical characteristics that demand unique structures at each end.”

First identified in 1974 during train testing on Japan’s then new 187mph ‘Sanyo’ shinkansen line, when people nearby noticed ‘booms’ near tunnel exits, the problem was solved by the invention of perforated portals extending from the tunnel entrance. Later, as train speeds gradually increased and further slight improvements in the control of micro-pressure waves were required, the solution was to radically enhance the train’s aerodynamics rather than retrospectively adding the pressure-dissipating portal extensions to tunnels that had already been built. The famous super-sleek, elongated aerodynamic snouts of Japanese high-speed trains cause the pressure to build up more gradually when the train enters a tunnel.

Building on over 40 years of research by the international rail community, the engineering team from HS2 Ltd, engineering consultancy Arup together with the University of Birmingham and Dundee Tunnel Research, developed and laboratory-tested HS2’s tunnel portal design.

To mitigate against ‘sonic boom’ HS2’s tunnel beneath the Chiltern Hills requires bespoke portal extensions. Protruding up to 220 metres – around the length of two full-size football pitches – from a chalky cutting near the M25 motorway, they are each punctuated along one side with ventilation portholes. These enable some air pushed forward by the train to escape, making the pressure increase more gradual so that the micro-pressure wave emitted from the other end of the tunnel is undetectable.

The portal at northern end is still under construction, the approach portal is longer, so will add about 300m to the bored tunnel length.

Unique HS2 tunnel portal completed to solve high-speed rail’s ‘sonic boom’ conundrum

Portal extensions' appearance on HS2 is first for British railway network

mediacentre.hs2.org.uk

 

[LNW-GW Joint]

Another weekly update from Northolt East (7 days, April 4-11):
Emily is at 4839m (+68m), Anne at 4715m (+133m).
This means they have 710m and 785m to go respectively, and the TBMs are only 124m apart.
No doubt there will be a break over the Easter holiday.

 

[Snow1964]

From the HS2 in your area map,

Bromford tunnels
Mary Ann 5560m, 40m to go, updated 21st April
Elizabeth 3440m, 2160m to go, updated 28th (sic) April

Northolt tunnels
Anne 4843m, 657m to go, updated 18th April
Emily 4992m, 557m to go, updated 18th April

In your area map

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

 

[absolutelymilk]

From the HS2 in your area map,

Bromford tunnels
Mary Ann 5560m, 40m to go, updated 21st April
Elizabeth 3440m, 2160m to go, updated 28th (sic) April

Northolt tunnels
Anne 4843m, 657m to go, updated 18th April
Emily 4992m, 557m to go, updated 18th April

In your area map

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

Great progress all round!

 

[GRALISTAIR]

Great progress all round!

Exactly my thoughts. Really good steady progress which is great to see. Thanks for posting the updates.

 

[TBMEngineer]

Progress is currently pretty rapid on the Downline (Emily)
Production record on our shift the other day at 13 rings in 10 hours.

Roughly 2 weeks and we will be finished.

Anne is roughly one month

 

[LNW-GW Joint]

Progress is currently pretty rapid on the Downline (Emily)
Production record on our shift the other day at 13 rings in 10 hours.
Roughly 2 weeks and we will be finished.
Anne is roughly one month

Looks like there will be a flurry of three completions in the next few weeks: Mary Ann at Bromford, Emily and Anne at Greenford.
No doubt there will be PR events to celebrate.
Elizabeth, the second Bromford TBM, just needs a boost with 2km still to go and relatively modest daily progress.
With the tunnelling out of the way (from OOC), attention will turn to the fitting out of the railway proper.

 

[absolutelymilk]

Progress is currently pretty rapid on the Downline (Emily)
Production record on our shift the other day at 13 rings in 10 hours.

Roughly 2 weeks and we will be finished.

Anne is roughly one month

Great work! Am I right that 1 ring is 2.0m wide?

 

[TBMEngineer]

Great work! Am I right that 1 ring is 2.0m wide?

1.9m
Thanks

 

[Geogregor]

No doubt there will be PR events to celebrate.

I'm not sure about how much PR there will be.

It seems that politicians mainly want HS2 to stay under the radar.

 

[TBMEngineer]

I'm not sure about how much PR there will be.

It seems that politicians mainly want HS2 to stay under the radar.

Could be, also all 4 NT tunnels are not breaking through in the normal fashion and are just going into a steel can.
Unlike atlas rd which was a proper breakthrough. There was a small bbc clip about NTW around a week ago on the machine. But yes