This map shows all trains (yellow pins) on the London Underground network in approximately real time (screenshot). Click the stations for a local map of that station.
Live departure data is fetched from the TfL API, and then it does a bit of maths and magic. It’s surprisingly okay, given this was done in only a few hours at Science Hackday on 19/20th June 2010, and the many naming/location issues encountered, some unresolved. A small number of stations are misplaced or missing; occasional trains behave oddly; some H&C and Circle stations are missing in the TfL feed.