New ‘Greenline’ App Tracks Trains in Real-Time

A new iPhone app that tracks the whereabouts of Green Line trains may not remedy a struggling system this winter, but it will help you navigate your ride in these arctic conditions. The ‘Greenline’ app, from ‘Where’s my MBTA Bus?’ creator Alex Grinman, uses GPS data to locate aboveground trains closest to users and track their progress on a rotating 20-second basis.

“Hopefully, riders will now be able to stay inside and be warm until the next train arrives,” Grinman said in an email to Boston. The 21-year-old MIT senior and Brookline native, who launched the app on February 13 in collaboration with Boston-based tech foundry Blade, is familiar with the unpredictability of the Green Line. “It’s just one of those problems that I’ve wanted to solve for a long time.”

Greenline’s less-is-more interface immediately identifies the user’s location, the nearest Green Line stops, and any running trains. But there’s one catch: tracking applies only to aboveground trains for now. Inbound users are out of luck once they hit Kenmore. Grinman hopes to add a crowdsourcing aspect or the ability to check up on recent Tweets to combat the lack of underground data going forward.

The app follows the long-awaited installation of tracking hardware in historically archaic Green Line trains. Each Green Line train now has a GPS device onboard which periodically broadcasts its position to the MBTA, Grinman says.

The MBTA, which has been looking to enhance the line’s technological capabilities since 2010, has made this new real-time data publicly available through its data feed. But the information is only accessible to independent developers like Grinman that are not associated with the MBTA. Though several Green Line tracking apps have popped up since the data was released, Grinman is confident that his app’s sleek, simple design will be a hit with frustrated Green Line riders.