First Off The Tube helps you board the Tube, Overground, and the DLR in order to be closest to your exits and interchanges at the chosen station. It incorporates a detailed database of each and every exit and interchange found on the Tube system and works perfectly well while youre underground as it needs no internet connection or GPS information. You can search by line, or just by the station name to find the station youre looking for.The app also provides information on the closest stations to a number of Londons tourist attractions and the Olympic venues. Enjoy!ps. if you have queries as to how to use the app or comments, do drop me an email, especially before leaving negative feedback. Thank you.