Transit authorities are investigating what led a green line MBTA trolley to derail Saturday morning.
The B line train was out of service and moving from a side track to the main tracks near Blanford Street when it derailed, according to transit officials. No one was injured and no passengers were on board.
As of around 9:30 p.m. Saturday evening, the train is back up and running. Route 57 buses provided substitute service along Commonwealth Avenue while MBTA crews worked to re-rail the trolley.
