I doubt there's an API, but you can see departure boards for most (London) tube stations online: http://www.tfl.gov.uk/tfl/livetravelnews/departureboards/tube/d

I doubt there's an API, but you can see departure boards for most (London) tube stations online: http://www.tfl.gov.uk/tfl/livetravelnews/departureboards/tube/default.asp?LineCode=northern&StationCode=EUS&NorthernGo=Go&switchNorthern=off http://www.tfl.gov.uk/tfl/livetravelnews/departureboards/tub... They're actually more detailed than the boards in the stations as they show current train locations.