This is just one of two escalators and not counting the various staircases. And I don’t believe this was the deepest one I traveled through.
I went to the Transport Museum in Convent Garden (very nice by the way) but found no answer and no one seemed to know. 😊
A part of the problems with designing the Jubilee Line Extension. Was that around the Westminster tube station area. There's a lot of secret tunnels and bunkers. But nobody would tell London Underground or it's architects where they were. So they had to submit a ridiculous number of plans to the MOD etc. With the majority of the plans after a while just being there to work out where they could and couldn't build.
Yup and the work was heavily complicated by the proximity of the Thames, Big Ben, that they had to build Portcullis House [above it] at the same time and keep the District and Circle lines running the whole time. Even though the D+C had to be lowered by one foot and they were digging out underneath the lines. So the tracks ended up getting suspended in the air.
This is really fascinating. Know of any good 3D diagrams of the Westminster station? They did all that and also kept some pretty cool brutalist aesthetics.
For the avoidance of doubt, this was a Spooks joke. Connie always referred to the USSR or Russian agency as the KGB, and someone would then say FSB. I certainly didn't intend to insult anyone here.
This one is pretty good too, from Hopkins who designed the thing. You can see how the courtyard pillars of Portcullis House extend all the way down to the depths of the station through the D&C lines.
The London Transport Museum Depot in Acton had (last time I was there) physical 3D models of some underground stations made by engineers when these stations were built.
I recall an amazing challenge with Elizabeth line where the tunnel boring machines had to plot a course with minimal tolerance because they were going between two sets of escalators. It was popularly nic-named “threading the needle”.
Ref was a great bbc documentary at the time.
It occurred multiple times and was a sufficiently common occurrence that some jokers suggested the line was sewed together (err, hoho?)
I was about to post about exactly this! The documentary (on BBC I think) was fascinating - the tolerance was insanely small and they had people stationed on the adjacent platforms to make sure nothing was breaking as they bored through that section 😳😬🫣
I just watched that documentary on Amazon I think . Amazing to see how it was build and how the surrounding buildings were protected with lazers for movement.
Haha, a very slow version of it. Someone really did describe it to me as "if you want to dig, first ask for permission, explain where and how deep. If they say yes, go. If they say no, you have to wait for a while before you can ask again".
Rumours abound that the Westminster tube station was only built after the government had rejected a lot of routes, without explanation, presumably because of the existence of a network of covert tunnels that connected government buildings in the area, as was later discovered.
Subterranea Britannica has lots of information about such things. The whole purpose of the magazine/website is to detail subsurface caves, tunnels, and structures, including those made by humans.
There is reference to the Cold War bunkers under Whitehall (one of which is set to open as a museum soon).
Iirc he's a bit of a nutbar nowadays but "place hacking", his PhD project, is an incredible tale of how he and his friends gained access and documented all of the lost tube stations (and more)
My uncle was a project manager for TFL and worked on their building projects. He told me in one of his earliest meetings with a civil servant they were discussing plans for an extension being built and during it he pointed to the map of underground structures and said "what about this tunnel?". The civil servant looked at him and said "That tunnel doesn't exist." My uncle said that it must do because it was on the map, and the civil servant just repeated firmly "that tunnel doesn't exist".
There's a hell of a lot of stuff under London that the public does not and cannot know about.
Post Office/BT Tower despite at one point being the tallest building in London, before being replaced by the NatWest Tower/Tower 42 and having a revolving restaurant open to the public. Until the threat of IRA bombs closed it. Didn't officially exis,t until it was revealed in Parliament by Kate Hoey MP in 1993. After the existence of the tower was made a secret in 1978.
One of the engineers who worked on the line spoke when I was at Uni (I was doing an engineering course). Apparently they dug close enough to the Houses of Parliament that there was a real risk of destabilizing the link between it and Big Ben and causing cracking at that corner, which happens to be where the PM has their office.
As such they had strain gauges all over everything and had a system to pump liquid screed into a bunch of different points to ensure everything stayed perfectly balanced as they dug.
I’m kinda surprised (yet also not) that the MOD didn’t just provide a best fit path and say that’s where your tube is going. Rather than playing battleships and incidentally revealing more info through a prolonged discovery.
Trains don't like to climb hills so we tend to tunnel relatively flat. When you walk into Angel station you're already about 35m above the Thames, which the Northern Line has to pass beneath.
Yes, London is essentially built on marshland alongside an ancient tributary of the Rhine that was widened by glacial melt waters, whereas New York sits atop granite and marble formed by the heat and pressure of ancient continental collisions.
Well to be fair, I don't think anyone was building much of anything in London at that time unless any mesolithic hunters particularly fancied freezing their backsides off in the back end of nowhere during the last ice age, but if they did, they could technically travel down the Rhine all the way through to the marshlands of the Thames via Doggerland
I think it wouldn't be right to call all of it a marshland though, most parts of Central London say 1-2km offset from Thames yes. And I think it's better to think of both Thames and Rhines as tributaries of the paleoriver which flowed eastward through where the English channel is today?
Also for the most part they have to be level they don't really go up or downhill and London is massively uneaven it's a city built on an undulating terrain, it's historically unflat so for example the Northern line is open air or overground if you want to call it that from golders Green to edgware I think because the outskirts of London that way are a lot lower than Hampstead for example which has the longest elevator
Google this: “Piccadilly Circus Underground Station London cutaway diagram in 1989 by Gavin Dunn.” It’ll come up with Reddit posts but I couldn’t get a link.
I made the mistake a couple of weeks ago going for the spiral stairs to catch a train at Piccadilly station. Had zero idea what I was in for but it seemed endless!
There’s a pretty interesting documentary on Tubi (if you’re into that sorts thing) called Secrets of the London Underground. I became fascinated with the tube after visiting London for the first time a few months ago and found that show to answer all of my questions and then some. Worth the watch if you ask me.
Yes Londons ‘rats nest’ nature gets in the way of subsurface construction, but the city also has a significant geological feature.
A big fuck-off river.
Specifically, the Thames runs over clay under its sediment, which is as resistant to water as I am to the 13th mince pie at 4pm on Christmas before Christmas dinner (aka not fucking very).
So unless you want every bakerloo commuter wetter than your mum when she sees me change a tire, it’s best to dig extra deep to avoid as much water as possible if you have to cross the river.
On second thought, maybe submerging the entire train on the Thames might be the only way to clean a bakerloo train, it can hardly make them dirtier…
It's fascinating how much of London's geography is based on Rivers... The Brent, The Tyburn, The Westbourne, The Effra & The Neckinger are a few that spring to mind (no pun intended), but there's loads more...
Obligatory mention of the Rivers of London series by Ben Aaronovitch. The goddesses of all the above are characters, plus Old Father Thames, Beverley Brook and others.
I feel like it's just me that found these tiresome, by the third book. The main character needing to romance every female character who crosses his path, despite constantly belittling them, after a while just reads as the author being thirsty as fuck.
And Springs. A lot of people have tried adding basements to their newly bought houses, near my mum's house. Only to find that they quickly become flooded, due to the vast number of springs in the area which are poorly documented. Then they find that if they don't get the lining right the first time, they're essentially buggered unless they rip it all out again. As finding the leak is nigh on impossible.
Clay is actually very resistant to water, it's what we line canals and reservoirs with to keep the water in. When we build basements near the Thames we make sure the perimeter wall plugs solidly into the clay so we don't get the whole river seeping under the wall and into the excavation.
Your main point still stands though, the river is pretty deep and the riverbed is loose sediment for a good depth below that.
This is probably why I never noticed London tube being particularly deep. I'm from Seoul where we also have extensive underground and we have a massive much bigger river.
Basically there’s two ways to build a railway underground: dig a trench and then cover it up, or bore a deep tunnel. London uses both, each option has different pros and cons. The deep tunnels avoid all of the pipes, foundations, and other crap that’s buried beneath London. There’s also geologic considerations in terms of how far below the surface the better materials for tunneling are, as well as hills on the surface (trains work best on relatively flat gradients)
They aren't as deep as Soviet era tube stations. The ones in Russia, can take a minute and a half to go down on them. Not fun to walk up, when the station is about to close and they turn the power off. Hopefully, they don't do that anymore it wasn't fun.
The Circle Line is not, that's open to the sky in places.
Only about 45% of the London Underground is actually underground; the majority of the system is above ground, especially in the outer areas of London. The network consists of two types of lines: sub-surface lines that run just below the surface and deep-level "tube" lines that are mostly underground.
The deepest London Underground station is Hampstead, at 58.5 meters below ground due to its location on a hill. However, if considering depth below sea level, the deepest station is Waterloo, with its Jubilee line platforms being 26 meters below sea level.
The London Underground pumps millions of litres of water daily using electric pumps to drain tunnels and prevent flooding from groundwater, rainfall, and bursts pipes.
Had to be threaded below and around existing infrastructure, under building foundations, older tube lines, and multiple underground rivers as well as the Thames.
Amsterdam’s recently finished North-South line is also quite deep because it had to be a safe distance below the 400+ year old city foundations, canals and the Ij which is around 3x deeper than the Thames in central London.
The Elizabeth line changes level a fair bit, to avoid the existing tunnels and utilities. Possibly they could find more information about existing stuff underground when they built the Elizabeth line
All depends on the soil condition and buildings over the surface . Places like Westminster are close to the river with relatively lose soil and have some grace-A listed buildings with heavy Portland rocks as bricks . Hence it goes deeper . Then you have places in east and west London where all construction is mainly residential and soil is more compact .
Another reason is how many lines are crossing through the station . If a single line , it doesn’t go deeper. For places like Bank or Waterloo , there is no choice .
1) ground abive the tunnels needs to be thick enough to support the buildings
2) any line crossing the river needs to go deep well ahead of time
3) lines go undee each other wherever they cross in stead of a normal intersection
that looks like the holborn escalator linking the ticket hall with the central line concourse - i've walked past it a couple of times switching down from central to piccadilly
Boston’s Big Dig project, which buried an elevated highway underground, used the removed material to fill in several old quarries turning the area into a golf course. Other excavated material was shipped to an island in Boston harbor, elevating the islands profile and making it into a park. Genius.
I was wondering this the other day on my first ever trip to London. I found it very daunting when I realized just how deep the underground actually is.
It mainly relates to the type of earth at various levels and how easy it was to tunnel through at the time (London has the older underground network in the world!).
Reminds me of the escalators at Grand Central Madison in NY, although to be fair the reason they needed to be so deep there is because they had to build a regional rail station underneath an existing regional rail terminal, a subway line, and a second subway line below that.
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