Using Next Tube a user selects a London Underground tube line and then looks up a station he is travelling from. He then indicates the direction (North, South, East or West) and Next Tube gets all the trains currently scheduled to run in that direction. It then counts them down in 5 second intervals so the user knows how long he has before the train arrives so he can hurry or take his time (or plan to take the next train). This is especially useful where the user has to go below ground where there is no network coverage.
Next Tube does not have a tube map - it is for users who know where they are going and simply want the latest available information to help them make their travel decision.
Next Tube is a simple App that takes a large quantity of data provided by TFL (Transport for London) and distills it into a few bytes of info about the next trains on London Underground thus reducing a users network costs since the typical message length returned is 50 bytes or even less