JR East recently launched the English version of their free JR East App, the "JR East Train Info".
Launched on 20th March 2015, the new app should prove invaluable to foreign tourists, allowing visitors to track the location of trains, monitor travel updates and JR announcements.
The app doesn't stop there, allowing users to track congestion along the Yamanote line trains, as well as the temperature of individual Yamanote line train carriages. The app also contains extensive information about the stations across JR East's network.
It marks a growing effort to provide more comprehensive information to overseas visitors, in light of growing inbound visitor numbers and the Tokyo 2020 Olympics on the horizon.