MBTA Conductor Free

This app will tell you prediction of arrivals and departures for the Subway, and Busses of the MBTA. Green line supported as well, but you will have to click on "Vehicle Locations" on the stop page . The MBTA has not yet got the Green Line predictions in yet, but you can use it to get the locations of those green line trains that happen to be above ground. I use it at Resevoir Stop Outbound on the D line every weekday.