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At first glance, it would be easy to assume that the photo above had come from one of Britain’s remaining mines. Indeed were it not for the presence of the ubiquitous orange jacket, it would be equally easy to assume that the photo was from a different time.

In fact the location pictured is far closer to home – it is a photo of Oxford Street.

With Tottenham Court Road Station closing to Northern Line passenger traffic today, it is perhaps inevitable that much of the media coverage will focus on the disruption this will cause. To a certain extent this is fair, as travelling to Tottenham Court Road is a key part of many people’s journeys. As the photo above suggests, however, the work underway at Tottenham Court Road is greater and more complex than many people realise. With that in mind, it is probably worth us returning to the station site and taking a look both at what has been going on there, and what will be happening during the upcoming closure.

For those interested, London Underground’s own explanation of the works can be found on youtube.

Tottenham Court Road is a station that is now almost uniquely unsuitable for the role it has to play. Standing at the heart of London, the station’s surface access, ticket hall and passageways are now  inadequate in relation to the role it plays.

A drastic reworking of the station’s sub-surface layout has long been needed and it is this that is now underway. By 2016 the station will have a completely new ticket hall, new access tunnels, lift shafts and escalators. It will also connect through to the new Crossrail Tottenham Court Road. It is a project this is proving a unique challenge.

One of the most obvious problems has been siting the construction. Digging the lift shafts, escalator boxes and access points for sub-surface construction requires space – and space is something that is at a premium at Tottenham Court Road. It was the need for this space that led to the demolition of the Astoria and other buildings around Centre Point (timelapse footage and photos of the TCR demolition work can be found here). That, combined with the closure of Charing Cross Road and the seemingly endless blue hoardings that face onto Oxford Street give the illusion of a large construction site.

Interestingly, however, it’s actually a site that is far more compact than it seems. As the photos below show, now that they’re well underway the construction work, spoil removal and other works are actually very tightly confined. Thanks to the variety of works underway it is an interesting site to watch in action, with diaphragm wall machines, Bentonite tanks and various other site machinery all working in close proximity.

The Diaphragm Wall machine goes about its business, with site work all around.

The Diaphragm Wall machine with St Patrick’s more clearly visible in the background, showing the condensed nature of the site.

Bentonite Tanks dominate the site skyline. Behind the works can be seen the current exit from Tottenham Court Road Station, with the temporary site offices constructed above it.

From a slightly lower angle, it is easy more obvious just how busy a site TCR is.

From a different angle, the work on Lift Shaft 4 is visible

Out beyond the blue frontings, life continues on Oxford Street.

Indeed the sheer value of space in the Tottenham Court Road area has also obviously had an effect on the construction techniques being used. In Yerkesian style, oversite construction is clearly a key part of the design. This is particularly evident in the new escalator box, where the piling and support works are obviously designed to support significant above-ground weight.

The Pile diameters can be over 2m with a length over 60m. 7 Oversite development piles were constructed with the Northern line Escalator Box to enable future development over this section of the station. These included some of the largest and most complicated piles ever constructed in London.

Another problem the station reconstruction has faced has been the utilities that run through the area. A large (and decidedly Victorian) sewer pipe runs down Charing Cross Road and the diversion of this, as well as a cast iron watermain, gas pipes and power and telecoms cables was the cause of much of the visible disruption on Oxford Street in recent months. A non-simple task already, this proved even more tricky due to the proximitity of all these utilities (some of which were sitting directly on top of each other) and the age of some of them. The fragility caused by age effectively meant that even though some were not directly vulnerable to the excavation work, they had to be relaid as there was a risk that the general movement of the earth the construction would produce would cause them to crack.

Sewer diversion works made tricky by the presence of a BT bank of ducts, 24″ trunk water and 18″ gas mains

The Eastbound diversion in place whilst utility diversion works are underway.

Whilst the above gives a good idea of what has happened so far, the question remains as to what comes next – what precisely it is that requires the Northern Line be closed at Tottenham Court Road for the coming months.

The answer to this actually lies in the station’s complex history. The station has been through three distinct iterations. It was first constructed for the (now) Central Line and opened in 1900, then “Oxford Street” station opened on the (now) Northern Line in 1907. This was effectively merged with the existing Central Line station in 1908, its above ground buildings eventually disappearing with the construction of Centre Point. Finally, like many stations, Tottenham Court Road was reworked to include escalators in the 30s.


This image showing the new layout of the station and its various tunnels gives an idea of the complexity beneath the surface.

View of tunnelling work to construct the new step free interchange tunnel (Northern to Central lines)

As the above paragraph suggests, beneath the surface, Tottenham Court Road station is thus a twisting and tight network of tunnels and passages – both for people and trains. This is a network that will be further complicated by Crossrail, which will be driving its own tunnels through the site in the coming years. Indeed the looming presence of the Crossrail tunnels is something that is having a noticable impact on the construction of the new Northern Line escalator box.

The Northern Line escalator box viewed from above.

Construction of this has reached the point where the dig is now just above the height of the incoming Crossrail tunnels. This means that the escalator box is not, as the name might suggest, actually cuboid. At its lower levels it has to be higher on the northern side and carry a 30 degree incline down to the south in order to allow the Crossrail tunnels to pass through the area untroubled. Its an interesting engineering challenge as those working on the site are happy to admit, as the growing incline makes working in the box with heavy machinery more difficult than would be expected.

Away from the escalator box though, it is the new lift shaft that will descend from the new ticket hall that is largely responsible for the upcoming disruption. It’s a vital part of the new design, not least because it will provide step free access to the Northern Line platforms. There is, however, a problem – at the level of the Northern Line tunnels, there isn’t actually enough room for it to sit between the two.

The new Lift Shaft is 30m deep and the base is in between the Northern line platform tunnels. It will allow step free access to the platforms from ticket hall

What will happen in this closure, therefore, is a rather delicate procedure. In crude terms, the two tunnels will be “nudged apart.”

Obviously, its a safe exercise, but one that requires some rather creative engineering. Without going into excessive detail, effectively the lining on one side of each platform tunnel will be modified and reinforced. This will change the profile of the platform tunnels slightly, allowing the lift shaft to be driven down between the two and completed. It is a complex procedure and carrying out this exercise with the Northern Line platforms still open to passenger traffic would likely have taken years – hence the decision to close.

All the above hopefully gives some idea into what is currently taking place at Tottenham Court Road. It is in an incredibly complex project, and one which is crucial to the future of the Underground network. It is also a project that, undoubtedly, has caused plenty of disruption and will certainly cause more in the months to come. Ultimately, however, it is important to remember that there is a reason for it – and that there is a lot more going on behind those blue hoardings on Oxford Street than it may sometimes seem.

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There are 30 comments on this article
  1. KG says:

    The Diaphragm Wall machine with St Giles more clearly visible in the background…

    That is in fact St Patrick R C Church on Soho Square, St Giles is in the opposite direction on the other side of Centre Point.

  2. John Bull says:

    Gah! You're right. Corrected – cheers.

  3. bubblecar says:

    How exactly do you 'nudge' two tunnels apart whilst trains are going through them? Does that mean that at the end of it all the tunnels will be further apart?

  4. John Bull says:

    @bubblecar the end result will be that the tunnels are technically further apart at that point then they are now.

    Its tricky to describe exactly what's happening – which is I suspect why its not featured really in TfL's Press Releases.

    It's more that they're skimming a chunk off the sides and the end result is that there'll be a bit more room between the platforms at that point (then they'll knock through the lift accesses etc.)

    If there's interest in it, I'll see if I can persuade those directly involved into doing a more technical piece on it.

  5. Chris M says:

    If I've understood what they're doing they're making the walls of the platform tunnel thinner (and squashing the tunnels slightly?) so there is more space between them?

    I'd certainly be interested in a more detailed post.

  6. Euston Throat says:

    "Tottenham Court Road is a station that is now almost uniquely unsuitable for the role it has to play. Standing at the heart of London, the station's surface access, ticket hall and passageways are now inadequate in relation to the role it plays."

    I'd add Camden Town to the list. Perhaps that's why you have chosen to include the degradation of 'unique'?

  7. Chris M says:

    @Euston Throat

    I'd suggest that Bank is another station that should be in that category, possibly also Victoria but that's not a station I'm particularly familiar with.

  8. Lara Ruffle says:

    Really enjoyed this article John. Thank you!

    Darryl1974 tweeted the article. :). http://twitter.com/#!/darryl1974

  9. Al says:

    I think each of the suggested stations are unsuitable in their own, unique, ways…

  10. timbeau says:

    Any chance of a colour key to that diagram – what's old, what's new, etc?

    Still think Tottenham Court Road is a silly name – and the temporary closure of half of it seems the ideal time to give it a more geographically specific name – Centre Point, perhaps? It would free up much needed space on the tube map too!

  11. Anonymous says:

    Great post JB – thanks.

    @ Chris M – I believe there is a plan to rebuild the Northern line station at Bank, involving a new platform tunnel for one of the lines. Can't remember where I read about though…

  12. jamesup says:

    But Charing Cross is the centre, no matter was 1960s property speculators might have wanted. You could call it St Giles Circus if you want to be proper about things.

    Or, just call it TCR (teeceeaar), all the cool kids are doing it.

    Great post. Cheers.

  13. Pedantic of Purley says:

    The ubiquitous orange jacket seems to be yellow to me.

  14. Pedantic of Purley says:

    Curiously today's (2nd April) TfL service update does not mention the station as being closed and the six month station lookahead gives the first day of closure as the 3rd April. However every other source (including this article if I have interpreted it correctly) implies it closed today.

  15. Chris M says:

    @Pedantic of Purley

    While the official closure of the station probably starts on Monday, it's effectively closed from today because the Northern Line is closed between Camden and Charring Cross for weekend engineering works (although it wouldn't surprise me if the TCR works are the principle reason for the line closure).

    I'm sure that this has been done with at least one other closure recently possibly the start of the Blackfriars works?

  16. Anonymous says:

    A marvellous post…

    …but dear me, that is an unflattering thumbnail for the YouTube video…

  17. Anonymous says:

    Fascinating post. I'm interested to hear more about nudging the northern line tunnels and the angled lift shaft — will that be unique on the tube?

    As I understand it, this station is being built with provision for crossrail 2 access. If that were ever to be built then TCR would be quite an interchange.

  18. Anonymous says:

    To be brutally honest, most rail transport in England is unsuitable all in their own, unique ways… this is what happens 100 years after being a pioneer.

  19. Pete In Colorado says:

    Based upon the diagram, it appears that the XRail station isn't below the Central/Northern stations but "off to the side/south?".

    Does this construction actually include the future Crossrail station? If not, does that mean that there will be another disruption when that is built?

    Just trying to get my bearings from across the pond.

    Pete
    Denver, CO

  20. Anonymous says:

    Fair question, Pete in Colarado. The TCR station work has been designed as one project, but there's more than one contract. Bond Street likewise. Others who comment here will have better detiala than I.

  21. mdk says:

    Great article, I have been curious to learn more about the construction. Future articles would be appreciated :)

  22. Anonymous says:

    @Chris M – the station isn't closed, only the Northern line. The Central line is still running through it and stopping as normal. You are right though ,the track closure is due to the redevelopment work. That's the reason given for the closure in the metro, press release,e-mail and station posters etc.

  23. Kaif says:

    Excellent article! Definitely needed after the Standard's recent "Travel Chaos" headline about the delays.

  24. Anonymous says:

    @Anon @ 10.08:
    your comment @Chris M implies that the Northern line itself is closed, which it isn't…. it's only the Northern Line part of TCR Station which is closed. Hence Northern Line trains are not stopping and there is no interchange.

  25. Chris M says:

    @Anon 12:27

    My comment related to the fact that the CX branch of the Northern Line was closed this weekend for the setting up of the works. As you say, from today the trains are running through without stopping.

  26. Anonymous says:

    Very interesting article

  27. dirtywhitecandy says:

    Fascinating – thank you. I especially liked your diagram of the current tangled station.

  28. timbeau says:

    The Central Line is getting pretty isolated these days.

    Going west from Liverpool Street, we get advised to "avoid" changing trains at Bank, no access to the Picadilly Line at Holborn in the morning peak, and now no interchange with the Northern Line at TCR. With the frequent outages on the Jubilee Line that only leaves Oxford Circus as the only interchange inside the Circle Line.

  29. Anonymous says:

    But we all know you can change at bank,it just involves walking down the length of the northern line platforms.

  30. Geoff - Brisbane says:

    Very interesting post, thank you. I look forward to more Crossrail posts like this, esp Canary Wharf.

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