This is a very simple app that displays the MBTA's Boston T map and when connected to the internet gives estimates of train arrivals. It's fast it's clear and it's very easy to use.
All arrival estimates come directly from the MBTA. Unfortunately the MBTA does not provide estimates for the Green line.
Please comment to let me know what you like (and what should be improved/added)! And if you have any problems feel free to email me.