As was promised in October, the MTA has launched an iOS application that displays real-time train information (Appstore Link). Currently, information is limited to the IRT lines (except the 7) and the Grand Central Shuttle. Also, there is no Android application at this time.
Just as exciting, for developers, hackers, and transit geeks is the release of real-time data feeds. This means that the same information behind the countdown signs available on many platforms is now available to developers. This is great news, and it means that we’ll see all sorts of unique applications of this data in the future. The MTA Developer Resources page has information on the various data sets and feeds available, including how to register for a developer’s API key for accessing real-time train and bus data.
via City Room