High Speed 2 (HS2)

[nito]

Originally Posted by llamaorama

I never really paid much attention to this project until recently.

Old Oak Common is just weird. It's going to only have one street going in and out of it, Old Oak Common Lane, which is only 2 lanes wide. It's meant to be a mega transfer stop but only to the Elizabeth line. The Central tube line and Overground lines are right there but not quite close enough to have a directly attached station. It's a very inaccessible and odd location.

I also still do not understand why they ruled out a connection to HS1.

On the other hand, Old Oak Common to the new Birmingham terminal does function really well as a "minimum operable segment", so it ensures the project can continue. If they weighed it down too much who knows what would have happened.

Old Oak Common Lane indeed isn't a major thoroughfare and I don't think it ever will be, even after OOC is built and the surrounding area redeveloped into a new district.

The Central Line is a bit too out of the way, and the two branches of the Overground's Mildmay Line are on the periphery of the site. There is a proposal for an out-of-station interchange with the Richmond branch of the Mildmay Line (and the proposed West London Orbital Line) at a new station on Old Oak Common Lane. There is an argument that you could have remodelled the area, but it would have been incredible disruptive. Not helped by the presence of the Elizabeth Line depot which is directly to the north of the HS2 station box.

The surface-level section (platforms 7-14) won’t just be served by the Elizabeth Line, but also Heathrow Express and all Great Western Main Line services (local, regional and intercity) all the way out to Reading, Bath, Bristol, Cardiff, south Wales and the South West of England, which adds a further 16 trains per hour on top of Elizabeth Line services.


Source: Wikipedia: https://en.wikipedia.org/wiki/Old_Oa...ailway_station

[nito]

Delta Junction
One of the most complicated pieces of engineering (that isn’t a tunnel), the Delta Junction is a completely grade separated multi-viaduct junction to the east of Birmingham that allows for London-to-Birmingham, London-to-Manchester and Birmingham-to-Manchester services to run without interruption.

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M6 South Viaducts
Images sourced from HS2: https://mediacentre.hs2.org.uk/news/...-viaduct-slide

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Cole River Realignment
The River Cole in Warwickshire has been realigned to allow for the Birmingham spur viaducts to be constructed as part of the Delta Junction
Images sourced from HS2: https://mediacentre.hs2.org.uk/news/...n-warwickshire

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Lawley Middleway Bridge
This is a 112m 1,631 tonne steel bridge that crossed the Lawley Middleway (Birmingham’s ring road) just before HS2 crosses the Cross City Line on its way out of Birmingham. Pushing the bridge across the road and railway means avoiding extensive closures to both.
Images sourced from HS2: https://mediacentre.hs2.org.uk/news/...ad-of-schedule

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Colne Valley Viaduct
Civil engineering works on the 2.1mile Colne Valley Viaduct have now been completed on what is Britain’s longest railway bridge.
HS2 have now completed the civilAt 2.1miles in length,
Images sourced from HS2: https://mediacentre.hs2.org.uk/news/...st-rail-bridge

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Northolt Tunnels
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Old Oak Common
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Birmingham Curzon Street
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[Busy Bee]

Damn that Colne Valley viaduct is one sexy bridge.

[UrbanImpact]

Originally Posted by Busy Bee

Damn that Colne Valley viaduct is one sexy bridge.

Agreed, and the the noise barriers aren't heinous for once.

[TowerDude]

I heard an interesting idea to help revive the whole HS2 Project AND get rid of Heathrow Airport's 3rd Runway at the same time.

The idea was to build a spur of HS2 that would go direct to Heathrow and then to basically ban all domestic flights to Heathrow, freeing up capacity for more international flights at the two existing runways.

I'm not against a third runway for Heathrow, but this HS2 Spur idea is VERY intriguing.

Dunno if the spur would originate from North or south of Old Oak Common Station.

[nito]

Originally Posted by TowerDude

I heard an interesting idea to help revive the whole HS2 Project AND get rid of Heathrow Airport's 3rd Runway at the same time.

The idea was to build a spur of HS2 that would go direct to Heathrow and then to basically ban all domestic flights to Heathrow, freeing up capacity for more international flights at the two existing runways.

I'm not against a third runway for Heathrow, but this HS2 Spur idea is VERY intriguing.

Dunno if the spur would originate from North or south of Old Oak Common Station.

Various options were considered to incorporate Heathrow into HS2, with tunnel/cutting/embankment/viaduct variations of
1) Through station on a loop
2) Spur station (junction for Birmingham/north only)
3) Spur station (delta junction for Birmingham/north and London bound)

Take the station; this would have to be built to the west of Terminal 5 (complicating proposed expansion of T5) and would need to be in excess of 50m below ground to avoid conflict with the existing Underground/Elizabeth Line/Heathrow Express station and the proposed western and south-western tunnel paths.

Ultimately they were all discarded on the grounds of i) adding excessive time to journeys, ii) introducing fragmented service patterns, iii) increased costs, and iv) less effective at providing mainline relief and serving Heathrow compared to an interchange at Old Oak Common because of the fragmented service pattern. This engineering report from 2012 provides insight into the various options: https://assets.publishing.service.go...t-heathrow.pdf (where the below images are sourced from).

An example route and station placement options.

[nito]

Project Update
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2025 in Review
- Installation of the very first high-speed platforms at Old Oak Common superhub station.
- The heaviest and longest single-stage viaduct deck slide on the project so far. At 345 metres, the Small Dean viaduct stretches over road and a railway in Wendover.
- A record first as engineers slid a massive 14,500-tonne box structure into position under the A46 Kenilworth Bypass. The structure, believed to be the heaviest of its kind in Europe, allows high-speed trains to pass under the dual carriageway.
- Successful excavation of two twin-bore tunnels – the 8.4-mile Northolt Tunnel in London and the 3.5-mile Bromford Tunnel in the West Midlands – marking completion of excavation for all 23 miles of deep tunnels on the opening stage of the railway.
- Completion of the project’s biggest natural river realignment. A 749-metre section of the River Cole near Coleshill was realigned to make way for new viaducts and embankments. The end result enhances habitats to maximise diversity.
- A UK-first as the final stages of a 320-metre viaduct slide were completed with traffic flowing below. The three-stage operation over the M6 in the West Midlands was brought to a successful close earlier this month.
- Completion of the 2.1-mile-long Colne Valley viaduct, which stretches over roads, lakes, the River Colne and the Grand Union Canal, north west of London. The giant pre-cast deck was completed last year and in 2025, engineers added the finishing touches, installing parapet sections, noise barriers, a structural health monitoring system and waterproofing and drainage.


Chiltern Tunnel
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Civil engineering works have now been completed on HS2's longest tunnels under the Chilterns. The 16km dual-bore tunnels will take less than 3-minutes to traverse. Images sourced from HS2: https://mediacentre.hs2.org.uk/news/...tunnel-project








Bromford Tunnel
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The final TBM has broken through on the 5.6km dual bore Bromford Tunnel which will carry trains below the eastern suburbs of Birmingham between Birmingham Interchange and the new Curzon Street station. Images sourced from HS2: https://mediacentre.hs2.org.uk/news/...l-breakthrough






Euston Tunnel
The fifth and final deep twin-bore tunnel on the London to Birmingham section of HS2 has now commenced. The first of two TBM's has now been launched from Old Oak Common heading 7.2km towards the HS2 terminus at Euston in Central London. On the final approach to Euston, the London-bound tunnel will split into two, having three tunnels on the final approach maximises the potential use of platforms and mitigates track conflicts, particularly as the station is being designed for a departure every 3 minutes. Plans for Euston station are still being worked on, but the site is clear.

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Chipping Warden Tunnel Green Tunnel
Some images of the 2.5km cut-and cover Chipping Warden green tunnel in Northamptonshire. Images 1+2 sourced from HS2: https://mediacentre.hs2.org.uk/news/...-warden-tunnel. Images 3+4 sourced from HS2: https://mediacentre.hs2.org.uk/news/...t-green-tunnel










Water Orton Viaducts / Delta Junction
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Work continues on the grade separated Delta junction, which is comprised of 3.7miles of viaducts. Once built, trains will be able to run through the junction at 360kph, with trains on the approach into Birmingham only needing to slow to 200kph. Images sourced from HS2: https://mediacentre.hs2.org.uk/news/...y-hs2-viaducts














M6 Bridge
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A 4,600 tonne 315m long viaduct was pushed over the M6 motorway in December at a rate of 12-13 meters per hour. Images sourced from HS2: https://mediacentre.hs2.org.uk/news/...6-bridge-slide










Bellingham Bridge
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Old Oak Common Station
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Curzon Street Station
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Various
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Images sourced from HS2: https://mediacentre.hs2.org.uk/news/...d-road-bridges

[jmecklenborg]

Thanks for the update. I like the welded truss in Birmingham. The narrator notes that such bridges are rarely constructed these days and I can't think of a single example built in the United States since about 1980. This sort of span now typically takes the form of a post-tensioned box girder, sometimes called a California Box Girder since I believe the technology was pioneered by California's department of transportation in the 1960s and 70s.

It is also impressive to see that the trains will operate at full speed in the long tunnel approaching Old Oak Common. Neither of the two long tunnels on the California High Speed Rail project will operate at top speed.

[Busy Bee]

It's amazing what can be built with a full funding commitment.

[Velvet_Highground]

Very impressive