In about a decade, the first HS2 train will arrive at London Euston station, and right now a huge construction site is preparing for that moment, with a chance last week to go and see what is happening.
Peering down from the HS2 offices into the basement of a former Euston station office block, this is a taster of what the rest of the site looks like today. This current site clearance is to make space for the new London Underground station that will be needed to handle the huge numbers of people arriving at Euston in a decade’s time.
However the main site is around the side and back of Euston station where a huge new underground box is being built to house 10 additional platforms for HS2 trains, along with all the support facilities, and further north, another construction site is building the approach tracks and tunnels.
A lot of land had to be cleared first, so that’s been a lot of old offices, some residential flats, and more famously, a huge graveyard, and all this is just one stage of the preparation works before the station construction can even start.
An entire road bridge got in the way at Granby Terrace that had to be demolished and rebuilt later in a more suitable height. However, it’s not easy to demolish a bridge that also happens to carry an awful lot of utility piles under the surface, all of which had to be diverted into either permanent new homes or given a temporary diversion while works are underway.
This is the difficulty of building in an urban site, someone else has already built something there before you, and it has to be dealt with.
When it opens, the station will offer trains every six minutes when it opens, rising to nearly one every four minutes when the full line is completed and will be expected to handle 166,000 passengers per day. To handle all those trains needs a lot more platforms if now it seems one fewer than originally desired. The HS2 platforms will be around 8 metres (26 feet) below ground level and will sit in a box that’s about 90 metres wide and 500 metres long.
The construction method is interesting.
A standard top-down construction will remove the soil down to just below platform level, piles are driven down, then the main supporting concrete slab will be poured. While they then start building upwards from the platform level, another team will dig underneath the concrete slab to create the basements needed for the train support facilities and station utilities.
The piles are also innovative.
Normally, piles are built by drilling a deep hole in the ground, dropping in a pre-assembled metal structure then filling up with concrete. So far the same, but the innovation is how they handle the top of the pile.
Normally, it’s pretty difficult to get the exact amount of concrete into the pile as some will settle so they overpour, then when it has all hardened, a team comes into manually clean off the top of the pile, breaking out the unwanted concrete. Not just a really unpleasant task for the workers, but noisy for neighbours and a waste of otherwise perfectly good concrete.
A technique developed here at Euston station by Lee Piper, working for HS2 contractor Skanska Costain STRABAG joint venture (SCS) and colleague Deon Louw from Cementation Skanska removes all the surplus concrete while it’s still curing using a giant vacuum machine that sucks it away.
That gives them a “zero trim” pile that is perfectly level with the ground and no need for extra manual labour to trim away the unwanted concrete. Whilst vacuum excavation technology is not new, using it in this way in the construction sector marks a step change, and it’s now being looked at for other HS2 sites where a lot of piles need to be driven into the ground.
The new piling technique is one step towards reducing the quite considerable disruption that a construction site of this scale can’t avoid causing. Apart from the several thousand residential neighbours who understandably would like there to be a lot less noise and dirt, they also have a number of institutions, including the Royal College of General Practitioners. That’s the building where budding GPs come to pass exams, and HS2 has an agreement to avoid construction work next to their building on GP exam days.
At the moment though, the site is still in the clearance and preparation stage before the main construction can even start. Apart from moving utilities out of the way – including soon a major water pipe running right along the side of the site, they have to start installing the thick concrete walls around the edges that will support the ground as they dig down to where the platforms will be.
Considering how vast and open the site is, one project that’s advancing is hidden from view underneath an acoustic shield is currently constructing a replacement ventilation and electricity supply for the London Underground to replace a small red-tiled building that had served that purpose. That former tube station building will be demolished, but not until its replacement is ready, and TfL’s heritage team have been over it taking all the good bits for their museum.
Over the next few years, the station will be dug down and built up to create the new HS2 station, but what happens afterwards is going to be of equal importance to the people who live and work in the area – the oversite development.
At the moment, even before the HS2 building site sealed off a large chunk of land, the Euston station and railway cutting was a rather unwelcoming area for residents and the lack of east-west travel added to journey times.
A major redevelopment is being planned, with offices to the front of the site closest to the busy main roads, and loads of housing to the rear closer to the existing residential estates.
When the Oakervee Review was published, one of the things it called for was a joined-up organisation to bring together all the parties involved at Euston to ensure there’s a single vision for the whole development. That’s the Euston Partnership, and apart from delivering a new railway station, arguably the biggest impact will be what the area looks like afterwards.
Looking at the recent redevelopment at King’s Cross where they had 67 acres to develop, Euston is slightly smaller at 60 acres, but aims to fit three times more development than was added at King’s Cross.
Part of the difference is that King’s Cross had a lot of surviving heritage, so it wasn’t possible to build lots of tall towers on much of the site, which gives Euston the capacity that King’s Cross lacked. However, that’s a mixed blessing, as Euston is almost a blank canvas and needs to be developed carefully to avoid becoming acre after acre of uniform blocks of buildings.
A lot of pre-planning work is going into liaising with locals to learn what is good, and what went wrong at King’s Cross. For example, the pedestrian link between King’s Cross and St Pancras station is great for taxis, but frankly, a bit of a mess for pedestrians. There’s a lot of thinking going into how to link Euston with St Pancras, mainly by creating a pleasant walking route away from the main Euston Road. At the same time, they need to ensure the route, though residential areas are pleasant for everyone, and that includes not annoying residents with the sounds of a thousand wheeled suitcases rumbling over pavements.
The eventual aim is for an estate built above a replacement Euston station that’s also a lot more permeable for people living around it rather than a “fortress Euston”, which is a bit how the station feels at the back today.
So above as below, Euston is being transformed.