They call it the London Underground, but how much of it really is under-ground?
London newbies might assume that every London Underground station is, indeed, under the ground. Likewise, it would be fair to assume that stations on the orange Overground line should all be above ground. But seasoned Londoners know that neither is true. Some Underground stations are overground and some Overground stations are underground. But how many, in each case?
According to TfL's website, only 45% of the tube network is in tunnel. There are 272 stations, so we can assume that around 150 (55%) should be open to the elements.
But hold on. It's not quite as simple as that. Some stations are both under-ground and above-ground. Take the familiar example of South Kensington. Here, the Piccadilly line is safely sheathed in tunnel, whereas the Circle/District is open to the skies. This is why TfL's stat tells us the percentage of the network (presumably the running track) that is below ground, and not the absolute number of stations.
We can still make a stab at counting, though. Handily, TfL makes available a map showing which bits of the network are in tunnels and which are not. Here, South Kensington is clearly shown to be both in tunnel and not-in-tunnel, depending on the line. So, if I assume this level of accuracy holds for the whole map I can simply count how many stations are open to the elements. And that is what I did.
I started off by making a count for each line. Some are easy. For example, the Victoria and the Waterloo and City each have zero stations above ground. The Northern has 14; the Bakerloo 9. But most lines share their tracks with other lines — for example, the Circle, Hammersmith & City and Metropolitan all run through Euston Square and Great Portland Street (both underground). So working out the totals for each line and then summing them would over-inflate the result, as such stations would be counted twice or thrice. The easiest way, then, was simply to work my way around the map, marking off stations as I went.
The grand total — assuming I counted correctly — is 154. Or, to put it another way, 154/272 = 56.6% of tube stations have at least some overground platforms. That's very close to the guess we made up top, based on amount of "network" underground.
Of course, there are many ways that pedants could quibble with this total. What counts as 'overground' or 'underground' is a subjective question. Many of the old cut-and-cover stations are very close to street level, with simple slab roofs over the platforms. These are counted as 'tunnelled' on the map, whereas stations with fancier roofs, like Farringdon, are not. Baker Street's Metropolitan platforms are partly under a roof and partly open to the skies, but are counted as tunnelled on the map. You could tie yourself in knots with such things. I've based my count purely on whether the official TfL map indicates a tunnel or not.
What about the Overground?
It's much easier to work out how many Overground stations are actually under-ground. Looking at the tunnel map, only seven are shown: Canada Water, Dalston Junction, Shadwell, Shoreditch High Street, Wapping, Wembley Central and Whitechapel (the latter only recently put underground by Crossrail works). That's seven out of 113 stations, or about 6.2% of Overground stations are actually underground. This is a much lower tally than underground stations being overground.
You'll have probably spotted a questionable inclusion in my list, in the shape of Shoreditch High Street. It's raised up on a viaduct, so, in no rational way can it be described as underground. Yet it has grey tunnel-worthy shading on the map, purely because the viaduct box has a roof. If I'm going to use TfL's map as the gospel, then I have to include it in my count. If I choose not to, then the tally for underground Overgrounds slips to six stations, or 5%.
So there we have it, there are 154 overground Underground stations, and seven (or six) underground Overground stations. Feel free to use these results next time you're setting a pub quiz, but expect lots of heckled challenges.
What about the DLR?
I honestly can't be arsed by this point. Sorry.
Why the hell did you go to all this trouble for something so trivial?
Because a reader asked (thanks Jane). And we listen to our readers.
