(Associated Press) - Massachusetts Gov. Charlie Baker says a passenger train carrying 50 people that left a suburban Boston station without a driver was tampered with.

The six-car train left the Braintree station shortly after 6 a.m. Thursday and traveled through four other stations without stopping before it was brought to a halt by cutting off power to the electrified third rail. No passengers were hurt.

Baker told Boston Herald Radio that the train was tampered with by someone ``who knew what they were doing.''

Joe Pesaturo, a spokesman for the Massachusetts Bay Transportation Authority, said the train's operator suffered a minor injury when brushed by the train at the Braintree station.

A spokeswoman for the Boston FBI office said it was in contact with transit police.

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