Recently released surveillance video shows the runaway Red Line train speeding through Quincy Adams Station in December.
The video was posted to the MBTA Transit Police YouTube page.
In December, the Red Line train left Braintree Station without an operator.
The video shows the train speeding through Quincy Adams and then Quincy Center stations.
Eventually, the train was brought to a stop just before North Quincy Station, when MBTA officials cut power to the track.
Dozens of passengers were on the train at the time.
The MBTA said it was caused by "human error" and eventually the driver was fired.
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