Tube Facts & Figures
Underground USA
Tube Stations that have no surface buildings
Central Line - Bank, Bethnal Green,  Chancery Lane, Gants Hill, Marble Arch, Notting Hill Gate, St. Paul's, Tottenham Court Road
Bakerloo Line-  Charing Cross, Piccadilly Circus, Regent's Park, South Kenton, Warwick Avenue
Piccadilly Line - Hyde Park Corner, Knightsbridge, Manor House, Piccadilly Circus, Turnpike Lane, Heathrow 4, Heathrow 5
Metropolitan Line - Barbican
Northern Line - Charing Cross, Bank, Old Street
Jubilee Line - Dollis Hill, Southwark, Swiss Cottage
Victoria Line-  Pimlico, Vauxhall, Walthamstow Central
District Line - Aldgate East, Mansion House, Westminster
There are tube stations which have entrances that are inside part of a National Rail building, so the tube station itself has no surface building, but the National Rail station does. Euston station is like this, as it the Bakerloo part of Paddington and Marylebone. (Waterloo station has the often forgotten about 'Shell Centre' entrance and exit, which is not part of the main National Rail station. Charing Cross is part of a public subway, and not the National Rail station of the same name).
Stations ticket offices are not are surface level, but you have to descend down steps before you can get to the point where you can buy a ticket.
Tube Stations that have no exit barriers
And thus, therefore you could enter and exit the system without a ticket ...
Chalfont & Latimer - Northbound platform, side entrance
Chorleywood - Northbound only, there's no barrier
Euston Square - Using the lift on southern side (Westbound Platform) of the stations, has no barriers, and is the only place on the Underground within Zone 1 that you can enter/exit the tube without touching in out
Finchley Central - On the west side of station, there is a side entrance which has no  barriers
Finsbury Park - Odd, as it's a big interchange station. But nope, you can walk right in ... (and out)
Kensington Olympia - Oyster 'self touch' in only for District and Overground services
Mill Hill East - One of the networks least used stations, not surprising really that it's ungated
Pinner - On the northbound platform, towards the back of the train there are steps down to ungated  exit
Roding Valley - Has no barriers on either side of the station, either exit/entrance!
South Kenton - No barrier gates here, just 'we trust you' Oyster touch pads.
West Harrow - When travelling westbound only, there are two 'self touch' Oysters, but no barriers
Woodside Park - But only when going northbound on the Northern Line
Tube Stations that have no escalators and use lifts to get down to the platforms
Central Line
Holland Park, Lancaster Gate, Queensway
Northern Line
Borough, Hampstead, Chalk Farm, Belsize Park, Goodge Street, Mornington Crescent, Tufnell Park, Kennington
Piccadilly Line
Covent Garden, Holloway Road, Russell Square, Caledonian Road
Bakerloo Line
Regent's Park, Elephant & Castle, Edgware Road, Lambeth North
Sidenote: Greenford for a long time used to be the ONLY tube station on the network where you can take an escalator up to platform level, but with recent (2010) rebuilding of Stratford station, there is now a (very short) escalator there to take you up to the Central Line platform level.
Also note that whilst all stations that have lifts have emergency staircases, some that have escalators also have emergency staircases that may be quicker to go down if the escalator is crowded! These stations (amongst those listed below), are Shepherd's Bush, Tottenham Court Road, Old Street and Moorgate
Tube Stations with  steps
All stations with lifts also have 'emergency' staircases to access the platforms too, but there are also some stations with escalators (not lifts) that also have stairs. Here's a complete list of them.
Hampstead - 320 steps (22 flat, 298 spiral)
Belsize Park - 189 steps (19 flat, 170 spiral)
[The station sign here incorrectly states that there are 219 steps]
Covent Garden - 193 steps
Russell Square - 171 steps (16 flat, 136 spiral, 19 curved)
[The station sign here incorrectly states that there are 175 steps]
Goodge Street - 136 steps
Elephant & Castle - 117 steps (18 flat, 99 spiral)
[The station sign here incorrectly states that there are 124 steps]
Tottenham Court Road - 116 steps (17 flat, 99 spiral)
[The station sign here incorrectly only refers to the 99  steps on the spiral staircase, but you have to walk the additional 17 flat steps making 116 in total]
Queensway - 126 steps (19 flat, 107 spiral)
[The station sign here incorrectly states that there are 123 steps]
Kentish Town - 117 steps
[The station sign here incorrectly states that there are 121 steps]
Archway - 113 steps
Tufnell Park - 116 steps (16 flat, 100 spiral)
[The station sign here incorrectly states that there are 110 steps]
Highgate - 107 steps
Borough - 102 steps
Old Street - 109 steps (9 flat, 100 spiral)
[The station sign here incorrectly only refers to the 100 steps on the spiral staircase, but you have to walk the additional 9, making 109 in total]
Camden Town - 96 steps
Holland Park - 93 steps (18 flat, 72 spiral, 3 more flat)
[The station sign here also incorrectly states that there are 92 steps]
Gloucester Road - 87 steps
Lambeth North - 84 steps (17 flat, 67 spiral)
Earl's Court - 83 steps
Embankment - 54 steps
Chalk Farm - 54 steps (19 flat, 34 spiral)
At Oval station, the sign says there are 80 steps. There are on the spiral staircase only, but there are additional steps before and after that which is bring it to a total of 103.
Aldwych station (disused) has 131 steps on its spiral staircase - seven lots of 17 on the spiral, plus 12 'flat' at the top - and then there are a further 21 steps from lower lift to platform (both platforms) level. A total of 152 steps between street and platform level.
Tube Stations that only have escalators
Some people don't like travelling on escalators, and have asked the question "Which tube stations have steps?". "All tube stations have steps!" is NOT the answer. The following stations only have escalator access to the platforms:
Angel, Baker Street, Baker Street, Bond Street, Chancery Lane, Bethnal Green, Holborn, Liverpool Street, South Kensington, Stockwell, Tooting Broadway, Tufnell Park, Vauxhall, Victoria.
(Admittedly, escalator can sometimes be turned off and not moving and thus become steps, but this cannot be relied upon).
Tube Stations with the most escalators
Since the re-development of Kings Cross St. Pancras with the new ticket hall, it now has 20 in total within the LU ticket barrier 'boundary'. There are an additional 2 'tube' escalators that take you from the ticket hall up to St. Pancras station, which would be 22 in total.
Waterloo also has 20 escalators (and two travelators!) within the official LU barrier,  but if you include the ones but the Northern/Bakerloo ticket area that take you up to the National Rail concourse, that's 3 more - a total of 23. Between 2016-2018 though, the Shell Centre entrance is closing rebuilding, meaning those two escalators are currently out of use.
Canary Wharf has 20 escalators inside the immense station that it is.
Westminster has an incredible 17 escalators - all of them to get you to and from  the Jubilee line.
London Bridge also has 17, the majority of these being for the Jubilee Line.
Bank has 15 escalators in total - as well as the travelator to/from the Waterloo & City line.
Oxford Circus has 14 escalators.
Green Park and Piccadilly Circus both have 11
Embankment, North Greenwich and Canning Town all have 10 escalators
Charing Cross has 10 if you include the 5 that were part of the Jubilee Line (but no longer in regular use)
The newly refurbished Tottenham Court Road station (opened in December 2015) has two new escalators from ticket hall to street, taking its total to 9 for the whole station
Euston, Canada Water, Bond Street and Southwark all have 8 escalators
Holborn and Warren Street have 7
Tube Stations that are 'Right Hand Running'
Tube trains and track normally 'drive' on the left as with roads in the UK .. trains will run on the left hand side. But there are a few exceptions on the London Underground where the tracks are switched and they run on the right instead, they are:
Baker Street, Bank, Euston, King's Cross, London Bridge, Warren Street, White City
Tube Stations with other/alternative names
As part of the name on the roundels:
Burnt Oak, still signed as 'Burnt Oak (Watling)'
Hillingdon, sill signed as 'Hillingdon (Swakeleys)'
South Wimbledon, still signed as 'South Wimbledon (Merton)' in some places
South Woodford, still signed as 'South Woodford (George Lane)'
Tooting  Bec, still signed as 'Tooting Bec (Trinity Road)'
Turnham Green, says 'Turnham Green - For Bedford Park' on the platform signs
Stations that are 'For...' somewhere on the roundel:
Warwick Avenue also says 'For Little Venice'.
Ladbroke Grove also says 'For Portobello Road'
Charing Cross also says 'For Trafalgar Square'
Holborn used to say 'Holborn (Kingsway)', but all these roundels signs have now been replaced (But see Howard Jones music video below)
Previous name of the station written into the tiles on the wall:
Arsenal, still has the name 'Gillespie Road'.
Hampstead, still has the name 'Heath Street'
Marylebone, still has the name 'Grand : Central' at the northern end of the platforms.
Warren Street, still has the name 'Euston Road'
Stations that are less than 60 seconds apart
These are all average timings from multiple journeys made going in both directions.
On the Piccadilly Line, Leicester Square and Covent Garden are the two closest stations together on the network with an average journey time of just 37 seconds.
Southwark to Waterloo on the Jubilee line takes on average 41 seconds.
The time between Charing Cross and Embankment (Northern) is 42 seconds.
Mansion House to Cannon Street (District and Circle) : 46 seconds
Northfields to South Ealing on the Piccadilly are so close to each other you can see the other each from the the other one looking down the line. Journey time is 47 seconds.
The time between Charing Cross and Embankment (Bakerloo) is 48 seconds.
Holborn to Chancery Lane on the Central takes 50 seconds.
On the Central Line, Oxford Circus to Tottenham Court Road  takes just 52 seconds
Cannon Street to Monument  (District and Circle) : 54 seconds.
Marylebone to Edgware Road on the Bakerloo, 55 seconds.
Bond Street to Oxford Circus  on the Central takes 56 seconds.
Warren Street to Euston on the Victoria line takes 57 seconds.
Swiss Cottage to Finchley Road on the Jubilee Line is 58 seconds.
Shepherds Bush Market to Goldhawk Road on the Hammersmith & City, Circle Lines takes 58 seconds.
Just missing out on the '60 second' mark:
It takes just over a minute - 62 seconds to do Wood Lane to Shepherds Bush Market, and 65 seconds to go between Latimer Road and Wood Lane.
Also, Fairlop to Hainault on the Central are surprisingly close. On a clear day you can see the the other station when looking straight down the line. Average journey time between is 65 seconds.
Stations that it takes longest to travel between
Chesham to Chalfont & Latimer (Metropolitan) takes 7 minutes, 20 seconds
Wembley Park to Finchley Road (Metropolitan) takes 6 minutes, 50 seconds
Heathrow Terminal 4 to Terminals 123 (Piccadilly - round 'the loop') takes 6 minutes, 20 seconds
Hammersmith to Acton Town (Piccadilly) takes 5 minutes, 50 seconds
Baker Street to Finchley Road (Metropolitan) takes 5 minutes, 30 seconds
Hammersmith to Turnham Green (Piccadilly) takes
Heathrow 4 to Heathrow 123            (Piccadilly) takes 4 minutes, 20 seconds
Arnos Grove to Southgate (Piccadilly) takes 4 minutes, 5 seconds
Waterloo to Kennington (Northern) takes 3 minutes, 50 seconds
Rickmansworth to Chorleywood (Metropolitan) takes 3 minutes, 50 seconds
Moor Park to Croxley (Metropolitan) takes 3 minutes, 45 seconds
Turnpike Lane to Manor House (Piccadilly) takes 3 minutes, 45 seconds
Chorleywood to Chalfont & Latimer (Metropolitan) takes 3 minutes, 40 seconds
Chalfont & Latimer to Amersham (Metropolitan) takes 3 minutes, 30 seconds
Waterloo to Bank (Waterloo & City) is 3 minutes, 25 seconds
Hampstead to Golders Green (Northern) takes 3 minutes, 15 seconds
Osterley to Boston Manor (Piccadilly) takes 3 minutes, 10 seconds
Seven Sisters to Finsbury Park (Victoria) is 2 minutes, 55 seconds
Kings Cross to Caledonian Road (Piccadilly) is 2 minutes, 50 seconds
Elm Park to Dagenham East (District) is 2 minutes, 50 seconds
Osterley to Boston Manor (Piccadilly) is 2 minutes, 50 seconds
Baker Street to St. Johns Wood (Jubilee) is 2 minutes, 40 seconds
Highbury & Islington to Kings Cross (Victoria) is 2 minutes, 35 seconds
Music Videos filmed on the tube
Boris Gardener - I want to wake up with you (1986) at Westbourne Park.
Howard Jones - New Song (1983) at Holborn
Aqua - Turn Back Time at Holborn, the disused Platform 5 to Aldwych
Paul McCartney - Press . Baker Street and Piccadilly Circus
The Kings - Do it again . Aldwych
Scissor Sisters - Mary . Canary Wharf
Chemical Brothers - Believe . Maida Vale
Soft Cell - Bedsitter . St. Johns Wood
Dolly Rockers - Je Suis Une Dolly (2009) on the Northern Line
Madonna - Hung up (2005) on the Jubilee Line
The Prodigy's 'Fire starter' was famously filmed in one of the lift shafts at Aldwych, but it could be any abandoned place really, and not readily identifiable as a tube station.
 
Tube Facts & Figures
What station has the most escalators? What station has the most stairs? Such things and more a constant source of fascination when it comes to the tube so I thought I'd list some of them.
TfL/LU though aren't very good at counting their own number of steps, so one of my favourite sections on this page is how many steps the official sign says there it, and then a note (where I've counted them) of how may steps there actually really are!