See inside HS2’s new Old Oak Common railway station

One of London’s largest construction sites can be found at Old Oak Common in west London, where a huge new railway station is being built.

When it opens in 2029-33, it’ll offer direct interchanges between the HS2 railway, the Elizabeth line and the Great West Main Line, mainly GWR services, out to south Wales and the west of England. It’ll also include provision for a future London Overground station next door, and even Chiltern Railways could call here.

When it opens, this “super hub” expects to handle as much as 250,000 passengers per day, with the majority swapping between lines – which will likely make it the busiest railway station in the UK. And shifting much of the intercity traffic off the existing railway tracks onto a dedicated high-speed line, creates space on the existing railway for a lot more regional and commuter services, reducing overcrowding in the trains.

That’s for the future though, and to get there, a huge new railway station needs to be built in west London, which is what’s happening right now.

Station layout (c) HS2

What had been a large railway depot and maintenance facility was cleared away to create space for the new station, which is being built partly underground for the HS2 platforms, and at ground level to link up with the GWR/Elizabeth line services.

To excavate the 850 metre long box that’s needed for the HS2 platforms, what is thought to be the UK’s longest diaphragm wall was constructed around the station. That’s done by digging down a 30 metre deep narrow trench and filling it with concrete to create a wall underground that surrounded the site.

Once the wall was created, and deep piles inserted, a concrete slab was cast at the ground level to support the walls, and then they started digging out the soil underneath the slab to excavate down 7 metres where an intermediate floor has been created.

This temporary floor is just there while huge beams are constructed that will eventually take up the job of supporting the box walls. If you’re familiar with Westminster tube station – it’s a similar concept – with a deep box and walls supported by large horizontal beams.

At the moment, about half of the 850 metre long box has been excavated down to the intermediate level, and they’re already digging down deeper, to the bottom where the HS2 trains will arrive in 6-9 years time.

The method of underdigging is pretty well established and deep down here, excavators slice away at the clay to reveal the vast space, and up at the surface, cranes hoist the soil up to be carted away.

Around 1 million tonnes of soil will be removed and will be taken by rail (of course!) to three locations – to fill in a disused pit near Cambridge for housing, landscaping at Cliffe in Kent, and landscaping a mining pit on the edge of Rugby that’ll become a nature reserve.

It’s expected that the excavation work will be completed by the middle of next year – leaving behind a vast long concrete box in the ground to be filled with the apparatus of a working railway station.

Using the international standard for measuring things — the station box is long and deep enough to be able to hold 6,600 Routemaster buses, that’s about two-thirds of all TfL’s buses in London.

The station box, at 850 metres in length is much longer than the train platforms, which will be 400 metres long, because on either side of the platforms will be crossover tracks allowing trains to swap between platforms as they enter and leave. The station also contains a “trouser” leg design, where the arriving track space is a bit longer than the departing tracks so that any heat built up by the trains in the tunnels can be removed before the train pulls into the passenger platforms.

Although the HS2 platforms will be below ground, the platforms for the GWR and Elizabeth line will be built alongside the HS2 section at surface level, and a single large roof will span over the whole site to create an integrated station.

On a very foggy visit, the area around the station looked almost as it has always looked, as the fog hid the towers that have sprung up around the area since it was announced that the HS2 station would be built here. People are already moving into an area that’s being described as west London’s Stratford — a site of regeneration driven by public transport upgrades.

When it opens, the connection between the different railways will become very important. People heading into London to go to, for example, the West End, the City or Canary Wharf will be able to avoid Euston and the rest of the Underground by swapping to the Elizabeth line at Old Oak Common.

A huge benefit though will be for people who would currently pass through central London — for example, someone travelling between Berkshire and Birmingham would currently come into Paddington, tube to Euston and then head to Birmingham. When Old Oak Common station opens, they can not only save upwards of an hour on the journey by skipping central London, they’ll save money as well.

That though is for when HS2 opens — at some point between 2029-33.

Some more photos: