The MBTA said no one was injured.
The Red Line train left the Braintree Station south of Boston just after 6 a.M. Today and was eventually stopped just past North Quincy Station when T personnel shut off power to the third rail.
T personnel boarded the train, and drove it north to the JFK/UMass stop, where passengers disembarked. The train was taken out of service for an investigation.
Massachusetts Bay Transportation Authority General Manager Frank DePaola called it a "highly troubling incident."