HS2 Old Oak Common

[Benjwri]

At the London end of the station, the new 6 track high speed station goes partly underneath the existing tracks. A trench needs to be dug for the 1.5m wide wall (diaphragm wall). In very simplistic form dig out a short length with what looks like a grab bucket and then fill it will concrete, doing it in small bits so hole doesn't cave in. The civil engineering process is rather more complicated than a quick description.

Clearly can only dig this if you lift track out of the way, then put it back again afterwards.

I don't know if this is happening at Old Oak, but normally the reinforcing rods are left protruding out of the concrete wall sections which finish about metre below surface, they are temporarily covered with wooden box or similar, and temporary fill put on top. At later date they are uncovered, reinforcement rods added to link the protruding vertical reinforcement and a huge capping slab cast in one large concrete pour. These pours will have parts that run all the way to other side wall to shop the two sides moving towards each other. For very long side these pours will be done in sections. My guess is it is these pours that will be done during the big closures as need access to a wider width, so need to tempo remove multiple tracks.

Once all the capping pours are done, track is back (although will probably have a speed restriction) and then station is built top down, (just dig out under the big concrete roof) adding more transverse props at intervals to keep sides apart. Eventually will get a base slab, and then be built up inside, although intermediate levels eg concourses might be cast as dig progresses downwards.

This will form some of the closures, but the main reason is the entire track area will need to be reconfigured for the GWML platforms. The track will all need changing into the new layout, connecting to existing track and the entire area resignalled. The obviously the entire station has to be built around it. Lots can be done with tracks open, but a lot of work above the tracks will require them to be closed, and there will be some pretty heavy TSRs

 

[Snow1964]

This will form some of the closures, but the main reason is the entire track area will need to be reconfigured for the GWML platforms. The track will all need changing into the new layout, connecting to existing track and the entire area resignalled. The obviously the entire station has to be built around it. Lots can be done with tracks open, but a lot of work above the tracks will require them to be closed, and there will be some pretty heavy TSRs

Building 8 platforms on a 4 track section ought to allow some new platforms to be built ahead of any track works as clearly first ones are to the side of the running lines.

It appears from the plan that most of the excavations are at the London end, this does mean that during any blockade it would theoretically be possible to lay in the high speed junctions (and overhead wiring) at the country end as the work side is few hundred metres (maybe a kilometre) to the west. The advantage of doing this is don't need to slew the tracks as work on each platform takes place, just change the points and clip them into whichever line is the temporary through track.

I have no idea if western end turnouts will be done during Christmas blockade, even if new track is not used for few years, or if someone has decided coming back later and having extra blockades is better more customer friendly option.

 

[The Planner]

There will be at least four blockades going up to 2028.

 

[hwl]

This will form some of the closures, but the main reason is the entire track area will need to be reconfigured for the GWML platforms. The track will all need changing into the new layout, connecting to existing track and the entire area resignalled. The obviously the entire station has to be built around it. Lots can be done with tracks open, but a lot of work above the tracks will require them to be closed, and there will be some pretty heavy TSRs

Building 8 platforms on a 4 track section ought to allow some new platforms to be built ahead of any track works as clearly first ones are to the side of the running lines.

It appears from the plan that most of the excavations are at the London end, this does mean that during any blockade it would theoretically be possible to lay in the high speed junctions (and overhead wiring) at the country end as the work side is few hundred metres (maybe a kilometre) to the west. The advantage of doing this is don't need to slew the tracks as work on each platform takes place, just change the points and clip them into whichever line is the temporary through track.

I have no idea if western end turnouts will be done during Christmas blockade, even if new track is not used for few years, or if someone has decided coming back later and having extra blockades is better more customer friendly option.

There will be at least four blockades going up to 2028.

There seems to be some confusion here between construction of the southeast corner of the station box (the next closures) and construction of the GW station

The rough plan for the GW station which has been covered several time before in greater depth (not too dissimilar to London Bridge):

1. Wait till the concrete batching plan for the HS station box is no longer needed and can be moved out of the way
2. Construct the 2 relief line platform island off line effectively outside the railway boundary
3. When relief line platform complete and plain line has been laid through, slew the relief lines at either end. Plain line - no signalling changes but probably some speed changes.
4. Slew main lines further north on to former relief line alignment, again plain line no new points or signalling changes
5. Construct southern (down) mainline platform island
6. Slew mainlines to pass either side of new southern (down) mainline platform island
7. Construct up mainline platform island (tight but not impossible space: 1 spare track width to the south and 2 spare to the north + up relief platform island
8. Lay plain line through platform where it isn't
9. New point and signalling time

e.g. the track is moved to allow the station construction as needed, the new layout is only put in at the end and until that point it is functional identical to the present arrangement.

 

[LNW-GW Joint]

Not sure if this has figured before, but work on the new NR station at OOC starts on 10 March, and will last until 2028.

Update on Old Oak Common conventional station works

The conventional station includes eight new platforms above ground that will connect the HS2 station to the Great Western Main Line, the Elizabeth Line services and an adjoining Station Control Area building. Works putting up concrete structures and installing drainage for the new conventional...

www.hs2.org.uk

Work on the new HS2 station at Old Oak Common is progressing well and the construction of the conventional station is expected to start on Friday 10 March 2023.
The conventional station includes a new station building and eight above ground platforms that will connect the HS2 Station to the Great Western Main Line and the Elizabeth Line services.
From Friday 10 March 2023, enabling works will start in the location identified on the map on page 2, and will include drainage and groundworks. Then the conventional station structure and walls to support the platforms will be built using concrete.
The eight platforms will be constructed in a phased approach, with platforms 3 to 8 initially built using precast concrete pieces bought into site and lifted into place. Then the main elements of the station roof will be built. These works are expected to be complete at the end of 2025. Network Rail will then divert the existing live railway through the newly constructed platforms over a Christmas possession period, which is expected to take place in 2026. After these works, Platforms 1 and 2 and the final section of the roof structure will be constructed with all these works expected to complete in 2028.

 

[Meerkat]

Nearly a year going past on the train looking at a largely completed empty station with nothing happening will be odd! A shiny station with very rusty track.

 

[Benjwri]

Nearly a year going past on the train looking at a largely completed empty station with nothing happening will be odd! A shiny station with very rusty track.

Presumably given delays they won’t even make that deadline of a year after estimated completion anyways!

 

[SCDR_WMR]

Presumably given delays they won’t even make that deadline of a year after estimated completion anyways!

What delay?

 

[Benjwri]

What delay?

Was a general comment on the huge delays which have plaugued every British rail infrastructure project in the past decade.

 

[LNW-GW Joint]

Was a general comment on the huge delays which have plaugued every British rail infrastructure project in the past decade.

A lot will depend on NR's GW route plan including remodelling and resignalling the area.
It's easy to lose a year when you only get one major blockade opportunity and resources are tightly constrained.
But lately, NR seems to have achieved most of its objectives during recent blockades.
HS2 has to build its side of the infrastructure too, of course, but doesn't have NR's problem of maintaining services into a major London terminus while doing so.

 

[swt_passenger]

Not sure if this has figured before, but work on the new NR station at OOC starts on 10 March, and will last until 2028.

Update on Old Oak Common conventional station works

The conventional station includes eight new platforms above ground that will connect the HS2 station to the Great Western Main Line, the Elizabeth Line services and an adjoining Station Control Area building. Works putting up concrete structures and installing drainage for the new conventional...

www.hs2.org.uk

That’s looking even less disruptive than the workflow suggested in post# 34 by @hwl - they’re now saying 6 of 8 platforms will be built before the first major track slews.

 

[reddragon]

Not sure if this has figured before, but work on the new NR station at OOC starts on 10 March, and will last until 2028.

Update on Old Oak Common conventional station works

The conventional station includes eight new platforms above ground that will connect the HS2 station to the Great Western Main Line, the Elizabeth Line services and an adjoining Station Control Area building. Works putting up concrete structures and installing drainage for the new conventional...

www.hs2.org.uk

That is currently an aspirational start date, there much still to be agreed!

 

[Fazaar1889]

HS2 OLD OAK COMMON AREA

New drone video showing the overall area.

 

[Bald Rick]

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.

 

[ShadowKnight]

Does the design of OOC HS2 still include passive provision for the hs2 hs1 link when that was a thing?

 

[zwk500]

Does the design of OOC HS2 still include passive provision for the hs2 hs1 link when that was a thing?

I don't believe so - the alignment might still be possible, but there is no provision in the Station Box construction for the additional tunnels that would be required.

 

[Bald Rick]

Does the design of OOC HS2 still include passive provision for the hs2 hs1 link when that was a thing?

No, not least because that wasn’t at OOC. That link was going to be ‘junctioned’ much nearer Euston.

 

[mr_jrt]

I swear the diagrams I saw showed three bores east of OOC, hence the original reason for the 6 platforms, with the centre two lines lining up with the centre bore which was for the link?

Edit: Not clear, but best I can find right now. From here.

 

[ShadowKnight]

Yeah I thought the centre bore was for hs1 as in was trying to understand why the track layout east of the platforms were much different from the western potion (and the victoria road crossover), as I don't understand the need for such complex trackwork east of the station there if solely designed for being a secondary London terminus

 

[Bald Rick]

I swear the diagrams I saw showed three bores east of OOC, hence the original reason for the 6 platforms, with the centre two lines lining up with the centre bore which was for the link?

Edit: Not clear, but best I can find right now. From here.
View attachment 129973

Yeah I thought the centre bore was for hs1 as in was trying to understand why the track layout east of the platforms were much different from the western potion (and the victoria road crossover), as I don't understand the need for such complex trackwork east of the station there if solely designed for being a secondary London terminus

Hmm. That’s interesting and I’d not seen that. I did go ‘HS2 blind’ for a couple of years in the early days. I stand corrected.

 

[zwk500]

Hmm. That’s interesting and I’d not seen that. I did go ‘HS2 blind’ for a couple of years in the early days. I stand corrected.

It runs parallel for a long while and several options were considered.
However, it has been quite firmly dropped and AIUI from posts above there is no provision on the construction of OOC to accommodate any later tunnel bores. It would be technically feasible to add them, but you'd need to close parts or all of OOC for rebuilding work.

 

[Benjwri]

It would be technically feasible to add them, but you'd need to close parts or all of OOC for rebuilding work.

Would it? I don't think the east end has any access from above, to get a TBM in or out you'd have to demolish a huge part of the station.

 

[zwk500]

Would it? I don't think the east end has any access from above, to get a TBM in or out you'd have to demolish a huge part of the station.

You'd have to tunnel from a Shaft or the other portal, you certainly wouldn't be launching from OOC. But you'd need to close the station when breaking through the concrete station box.

 

[Bald Rick]

You'd have to tunnel from a Shaft or the other portal, you certainly wouldn't be launching from OOC. But you'd need to close the station when breaking through the concrete station box.

I have stood in the part of the box where the tunnels to Euston will emerge, and there’s no space for another bore.

 

[mr_jrt]

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.

 

[zwk500]

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

That plan looks quite old, given the lack of a scissors to the west and the outer bores not appearing to have any connections to the centre island

 

[Sebastian O]

Eight platforms at surface. What’s the plan?

Up and down reliefs
Freight spare
Terminating platform for Elizabeth line services extended from Paddington?
Up and down mains
Two further up and down mains?

 

[zwk500]

Eight platforms at surface. What’s the plan?

Up and down reliefs
Freight spare
Terminating platform for Elizabeth line services extended from Paddington?
Up and down mains
Two further up and down mains?

Up Relief, UR Loop, Down RL, DR, UML, UM, DM, DML. 8 lines, 8 platforms. Central Relief line platforms used to turn XR trains back but capable of running through as well, Main Lines will largely be trains in same direction alternating platforms, IIRC.

 

[Benjwri]

Two further up and down mains?

Yes the frequency on the mains means they cannot stop on one platform. Same reason two platforms are used in each direction at Reading.

 

[mr_jrt]

That plan looks quite old, given the lack of a scissors to the west and the outer bores not appearing to have any connections to the centre island

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.