HS2 Old Oak Common

[zwk500]

Yep, file is dated 2012, though as I say, you would imagine it would have been cheaper to connect the centre lines to the outer bores and leave everything else (i.e. the station box) as designed.

Given how early the HS1 link was dropped, they may well have chosen to move the portal locations to give a smoother alignment and better pointwork.

 

[Benjwri]

you would imagine it would have been cheaper to connect the centre lines to the outer bores and leave everything else (i.e. the station box) as designed.

Depends how early in the process they were removed, box is a fairly simple design and the removal of a hole in one wall will have warranted some recalculation anyways. I also wonder if they moved the other two bores together, and then they would’ve been able to save money on excavation, ventilation shafts etc.

 

[Bald Rick]

I didn't think they'd excavated down to the bottom yet? I found a clearer plan, has the box been redesigned again? I presumed they'd just delete the middle bore and associated pointwork and leave everything else the same.

View attachment 129997

Yep, file is dated 2012, though as I say, you would imagine it would have been cheaper to connect the centre lines to the outer bores and leave everything else (i.e. the station box) as designed.

What you have above isn’t a design, far from it. The design has happened much more recently. The portal, and the approach to it, is 2 tunnels wide.

 

[Snow1964]

Transport and Works order for access for Great Western mainline at Old Oak has been applied for (it is where Jewsons currently is), and document has plans and why etc

Application to confer powers to compulsorily acquire land, rights in land and powers to carry out works to create a compound on the south side of the Great Western Mainline between Acton West Junction and Kensal Green Junction to support the delivery of changes to the railway infrastructure and the construction of HS2’s Old Oak Common station.

Old Oak Common (Great Western Mainline track access): Transport and Works Act order

Approval for Old Oak Common (Great Western Mainline track access) TWA order.

www.gov.uk

This is Network Rail description, requesting temporary change of use from builder's merchant to construction compound for 8 years (which would be to mid 2031)

Old Oak Common lineside logistics compound - Network Rail

Old Oak Common compound will support the delivery of changes to the railway infrastructure and the construction of Old Oak Common station.

www.networkrail.co.uk

 

[SECR263]

Good video. It shows clearly the meaning of ‘going round the houses’ with respect to the conveyor!

Also it shows what a shame it is that the Elizabeth Line depot wasn’t built with over site development in mind. That would be one very valuable piece of real estate.

Apologies if already stated but what does conveyor convey to or from site. Also at far end of site (west) after the Birminham line turn off, now no more, there are a couple of old buildings which were rail connected from Brum line and still standing (large garage size). At the bridge near these a lot of reinforcing is taking place on bridge wall. Was this failing or future insurance. The slow lizzy lines go under. Thanks

 

[LNW-GW Joint]

The conveyor takes spoil from several points in the OOC work area (and from the TBMs when they start up), and delivers it to Willesden Euroterminal to be loaded into trains which take it to landfill points.
In the other direction tunnel segments and other supplies are unloaded from trains and are then distributed around the OOC site.

 

[Bald Rick]

The conveyor takes spoil from several points in the OOC work area (and from the TBMs when they start up), and delivers it to Willesden Euroterminal to be loaded into trains which take it to landfill points.
In the other direction tunnel segments and other supplies are unloaded from trains and are then distributed around the OOC site.

For clarity, the elevated conveyor is only taking spoil away. Tunnel segments for the Northolt (East) tunnel that is being bored from OOC are being delivered by road from the railhead at Willesden Euroterminal.

The logistics tunnel will be used for spoil out and segments in for the Euston tunnels.

 

[zwk500]

The logistics tunnel will be used for spoil out and segments in for the Euston tunnels.

We hope!

 

[Bald Rick]

We hope!

it will

 

[59CosG95]

it will

Is it the case that the Logistics Tunnel has become a pre-requisite?
If so, it does make sense to put the main works on ice until the "LT" is complete.

 

[Bald Rick]

Is it the case that the Logistics Tunnel has become a pre-requisite?
If so, it does make sense to put the main works on ice until the "LT" is complete.

My understanding is that the logistics tunnel is required before the Euston tunnels can be bored, yes.

 

[itsnotpete]

On that note...

HS2 confirms that work on the Euston Tunnel is to be paused | New Civil Engineer

The tunnel’s schedule was thrown into doubt after the Euston station project was put on hold last month, with spiralling costs due to inflation cited as

www.newcivilengineer.com

 

[hwl]

Is it the case that the Logistics Tunnel has become a pre-requisite?
If so, it does make sense to put the main works on ice until the "LT" is complete.

My understanding is that the logistics tunnel is required before the Euston tunnels can be bored, yes.

On that note...

HS2 confirms that work on the Euston Tunnel is to be paused | New Civil Engineer

The tunnel’s schedule was thrown into doubt after the Euston station project was put on hold last month, with spiralling costs due to inflation cited as

www.newcivilengineer.com

As everything HS2 construction work related at and around OOC is behind schedule and the overall pressure to attempt to catch up is effectively off it does make sense to delay the start of Euston tunnel for at least 6-9 months rather than sticking to schedules in older plans.
The may also be a useful optimum scenario for TBM etc staff finishing on other machines to then moving to OOC-Euston after other bores (which are mostly delayed as well) are completed.

 

[LNW-GW Joint]

Nobody has owned up to delays in the HS2 programme (bar the parts recently paused).
But it seems clear the milestones put out last July (mainly for tunnelling) are under pressure.
The next 6-monthly parliamentary report by DfT due in May will be closely scrutinised.

 

[BananaRepublic]

Is it the case that the Logistics Tunnel has become a pre-requisite?
If so, it does make sense to put the main works on ice until the "LT" is complete.

My understanding is that the logistics tunnel is required before the Euston tunnels can be bored, yes.

My understanding (correct me if I'm wrong) is that on completion, the logistics tunnel TBM shield and cutting head will be dismantled and brought out through the OOC station box.
The Euston Tunnels TBM's will then be delivered and assembled via the station box, in readiness for the intended tunnelling drive.
That all has to be completed before the HS2 station construction can be progressed.
It can't be done after opening the HS2 platforms.



m

 

[Bald Rick]

My understanding (correct me if I'm wrong) is that on completion, the logistics tunnel TBM shield and cutting head will be dismantled and brought out through the OOC station box.
The Euston Tunnels TBM's will then be delivered and assembled via the station box, in readiness for the intended tunnelling drive.
That all has to be completed before the HS2 station construction can be progressed.
It can't be done after opening the HS2 platforms.



m

as above, the Euston tunnel has to be complete before the OOC station can be substantially constructed. I have stood at the portals for the Euston tunnels, and it’s not far away at all from the station itself.

 

[BananaRepublic]

as above, the Euston tunnel has to be complete before the OOC station can be substantially constructed. I have stood at the portals for the Euston tunnels, and it’s not far away at all from the station itself.

Can you explain why the tunnels need to be completed?
If the TBM's are installed, initial tunnelling commences and all logistics (spoil removal, tunnel segment delivery, access and other items) are carried out via the Atlas logistics tunnel, then surely nothing needs to affect the completion of the OOC station.
All work and access will then be carried out to the east of the station box.

The plan has been in place for a while now, for OOC to start operations, before Euston was ready.
How far was tunnelling expected to have progressed under that previous timetable?


m

 

[LNW-GW Joint]

I'm sure others will know better, but the original plan had Euston tunnelling complete by the end of 2025, after an 18-month drive starting in early 2024.
This was independent of the station plan for Euston itself, and tied in with the station plan at OOC.
The logistics tunnel is supposed to be complete by the end of 2023, allowing the Euston TBMs to be assembled and launched soon after.
We'll just have to see what the new tunnelling schedule is.

As I understand it, the cost of tunnelling is largely driven by the skilled resource needed for the TBM teams - at least 60 people per TBM (3 shifts of 15 plus spares).
I can well understand HS2 needing to optimise those costs by reducing the number of TBMs in use simultaneously.
For example, it is looking increasingly likely that the Chiltern tunnels will complete before the Euston tunnels need to start.
If the Chiltern crews could then transfer to the Euston job, it would generate a major cost saving.

 

[Meerkat]

What's happening to the Euston TBMs when they reach Euston - will they need pulling out at the OOC end?

 

[LNW-GW Joint]

What's happening to the Euston TBMs when they reach Euston - will they need pulling out at the OOC end?

They'll probably be dismantled on the spot, some distance from Euston itself..

 

[dosxuk]

What's happening to the Euston TBMs when they reach Euston - will they need pulling out at the OOC end?

As a general rule, you can't back a TBM up - with lined tunnels, the cutting heads are bigger than the tunnel they leave behind - so if you've got to have enough space to dismantle the head at the destination, you may as well dismantle the rest of it there too.

There are exceptions - you might not have any space, and decide to just divert it off the tunnel route and bury it instead (as done with the channel tunnel and IIRC some of the Farringdon bound machines for crossrail); or you might want to reuse the entire machine after a short tunnel and it's easier to chop the head off and pull the rest back for the next job, moving the head round outside the tunnel (Long Itchington Wood tunnels are being done this way).

 

[Bald Rick]

Can you explain why the tunnels need to be completed?

I can’t, as I’m not the expert on it. However the logistics for getting the material in/out is significant. Clearly some parts of the station can be progressed with, but much cannot.

 

[BananaRepublic]

I can’t, as I’m not the expert on it. However the logistics for getting the material in/out is significant. Clearly some parts of the station can be progressed with, but much cannot.

That’s what the Atlas logistics tunnel is for.
Only the TBM’s and some other things need to be introduced via the station box.
Once the drives commence, all logistics will be via the LT and the station construction can progress to completion.

 

[Dave_Cardboard]

For those interested in the GWML track layout at OOC, there's a planning application at OPDC that includes the (latest) iteration of the track layout including provision for links to the Chiltern line. It shows 4 platform faces on the GWML Relief lines with 3 turnback sidings to the West.

Link to full planning application (for revised Old Oak Common Lane bridges)... https://planning.agileapplications.co.uk/opdc/application-details/10012

Here's a clip of the location plan therein indicating the western track layout...

 

[tomuk]

For those interested in the GWML track layout at OOC, there's a planning application at OPDC that includes the (latest) iteration of the track layout including provision for links to the Chiltern line. It shows 4 platform faces on the GWML Relief lines with 3 turnback sidings to the West.

It also shows the reinstatement of the link to the NNML, a single track link from the UP Relief. Shame it can't tuck in behind the turnback crossovers.

 

[kevin_roche]

It also shows the reinstatement of the link to the NNML, a single track link from the UP Relief. Shame it can't tuck in behind the turnback crossovers.

Interestingly there appear to be three tracks from the NNML one of which goes over the Chiltern Line Bridge and the others over the northern end of the GWML bridge. On another drawing, the most northerly track is marked as Potential Future Chiltern Line Tracks. A selection of that drawing (Site_Plan_-_1CP02-~4.PDF) is shown below. I'm glad that enough space to extend the access in the future if needed has been retained. I read that earlier plans did not allow that.



The written statement attached to the planning application (linked in post #1031) says:

The works for approval are associated with the replacement of the existing Great
Western Mainline (GWML) and Wycombe Line bridges with two new bridge
structures which are required due to the realignment, widening and lowering of
Old Oak Common Lane (approved under planning ref. 20/0011/HS2OPDC) and the
realignment of the GWML tracks, as well as future proofing for the potential
extension of Chiltern Line services to the new Old Oak Common station within the
disused Wycombe Line corridor. The extended concrete bridge and new steelwork
bridge provide support for three new railway tracks over Old Oak Common Lane
comprising two Chiltern Line tracks (Up and Down) and a crossover track
reconnecting to the GWML.

Edit:

It seems to me unlikely that they would build a new bridge unless there is at least a tentative plan to use it. What is being shown here is a plan for two bay platforms at OOC to be added at some point.

 

[Meerkat]

If they are replacing the GW bridge due to a widening of Old Oak Common Lane then that will be a lengthy blockade wont it?

 

[zwk500]

If they are replacing the GW bridge due to a widening of Old Oak Common Lane then that will be a lengthy blockade wont it?

Depends how they plan to do it. Could be a weekend job if everything can be prefabbed and a Crane can get near enough.

 

[Meerkat]

Depends how they plan to do it. Could be a weekend job if everything can be prefabbed and a Crane can get near enough.

How long did the Ravenscraig one take? And that would be tricky to replicate here without closing the road and causing access problems for a long period.

 

[zwk500]

How long did the Ravenscraig one take? And that would be tricky to replicate here without closing the road and causing access problems for a long period.

Don't know, not too long, but wasn't that an emergency replacement not a planned job?

In theory, if you prefabbed the abutments and were able to assemble the bridge in a compound on-site so that it could be craned in you could do it in a short blockade, maybe a Bank Holiday/Christmas weekend or a 9-day blockade depending on exactly what needs moving.
Take block friday night, lift track off, dig out the new road depth, crane in the concrete abutment building blocks, backfill, then crane in the deck and restore the railway by Monday morning is not impossible, although it would be exceptionally tight depending on the amount of services in the road etc. You could then take OOC Lane down to 1 lane for a sustained period with temporary traffic lights while working on each side to finish off the final road width/any pedestrian paths etc.