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Accident Report Detail

Collision of Two Massachusetts Bay Transportation Authority Light Rail Passenger Trains

Executive Summary

On Friday, May 8, 2009, about 7:14 p.m., westbound Massachusetts Bay Transportation Authority (MBTA) Green Line train 3612 struck the rear of standing westbound MBTA Green Line train 3808 near Government Center Station in Boston, Massachusetts. The accident occurred in the underground tunnel segment on the Green Line of the MBTA subway system. Each train consisted of two light-rail "married-pair" railcar sets. One car from each train derailed upright as a result of the collision. Sixty-eight injured passengers and crewmembers were transported to local hospitals. Monetary damages were estimated to be about $9.6 million.

Probable Cause

The National Transportation Safety Board determines that the probable cause of the May 8, 2009, collision of two Massachusetts Bay Transportation Authority Green Line Trains in Boston, Massachusetts, was the failure of the pilot operator of the striking train to observe and appropriately respond to the red signal aspect at 744A because he was engaged in the prohibited use of a wireless device, specifically text messaging, that distracted him from his duties. Contributing to the accident was the lack of a positive train control system that would have intervened to stop the train and prevent the collision.

Accident Location: Boston , MA    
Accident Date: 5/8/2009
Accident ID: DCA09MR004

Date Adopted: 4/13/2011
NTSB Number: RAB-11-06
NTIS Number:  

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