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Green Line crash ‘would have been prevented’ if MBTA had installed train tech earlier, NTSB finds

Investigators at the scene of a crash between two Green line T trains near 971 Commonwealth Ave.Barry Chin/Globe Staff

A Green Line crash in July 2021 that injured 27 people was caused by an operator speeding at 33 miles per hour, as much as 23 miles above the limit, the National Transportation Safety Board announced Thursday.

The crash “would have been prevented” if the MBTA had installed a long-discussed system on the Green Line that automatically intervenes and applies brakes to prevent trains from speeding or getting too close to each other, the NTSB’s final report on the incident said. The technology, first recommended by the NTSB 14 years ago, won’t be in place on the Green Line until June 2025, the report said, far later than the MBTA had previously said it would be completed.


The incident occurred at around 6 p.m. on July 30, 2021, as two Green Line trains were both traveling west on the B branch on Commonwealth Avenue, and one crashed into the rear of the other. The striking train accelerated at “full power” for about 500 feet between the St. Paul Street station when the operator “reported a loss of situational awareness,” the report said, and did not apply the brakes before the crash. The train that was hit derailed and traveled about 240 feet, the report said. Twenty-four riders and three MBTA crew members were transported to the hospital with minor injuries, according to the report. The maximum speed limit on the Green Line ranges between 10 and 25 miles per hour, the report said. However it noted: “In this accident, the striking trolley was over-speeding by about 23 mph.”

The driver of the striking train, Owen Turner, is facing a misdemeanor negligence charge. He has pleaded not guilty, and his trial in Brighton Municipal Court is scheduled to begin on Jan. 10. The MBTA fired Turner, the NTSB report said. The MBTA estimated equipment damage from the crash to be about $2 million, the report said.


The crash was the first in a long series of serious safety incidents that have plagued the agency over the last year and a half, including another Green Line crash and derailment that sent three operators to the hospital in June.

The NTSB first recommended the MBTA install a train collision prevention system on the Green Line — called positive train control — in 2009 following a collision that year that injured 49 people and another in 2008 that killed a train operator. The system applies brakes as one train approaches another, even if an operator doesn’t apply them.

In 2019, 10 years after the NTSB’s recommendation, the MBTA awarded a contract for an alternative, less expensive safety system that it said will accomplish the same benefits. The T said previously the technology would be fully implemented in December 2024.

Last year, the T announced it was transferring around $45 million from its operating budget, for day-to-day needs, to its capital budget, for longer-term projects, to complete the project in 2023. That decision was later criticized by the Federal Transit Administration as part of its safety management inspection of the agency which found the T has been prioritizing long-term projects over day-to-day maintenance and safety.

The MBTA stopped providing monthly updates about the project on its website after September 2022. The NTSB report said the implementation of the crash prevention technology has been delayed again, this time until June 2025. Around two hours after the NTSB released its report, the T’s website changed the completion date for the project from “late 2023″ to “June 2025.”


On the day of the 2021 Green Line crash, Turner started his shift at 3 p.m., the report said, and his trolley’s “event recorder indicated at least three occurrences of speeding” during his shift, the report said. The MBTA hired Turner on Sept. 22, 2014, the report said, and had eight documented disciplinary actions for six policy violations, the report said, including two for speeding.

MBTA rules require Green Line trains to remain 500 feet apart in most circumstances, according to the report.

NTSB investigators found that the train’s brakes were working correctly after the incident, and Turner tested negative on a post-accident alcohol breath test and a urine drug test. Turner’s workload and work schedule were not contributors to fatigue, the report said. “The investigation did not determine the cause of the operator’s loss of situational awareness,” the report said.

Taylor Dolven can be reached at taylor.dolven@globe.com. Follow her @taydolven.