Shuttle buses are replacing train service on the Green Line Extension until further notice as authorities investigate Tuesday’s train derailment near Lechmere Station.
The MBTA said Wednesday that it’s unclear when normal service will resume between North Station and Union Square and between North Station and Medford/Tufts.
“Safety continues to be our top priority, and this incident is unacceptable,” MBTA General Manager and CEO Phillip Eng said in a press release. “We’re working alongside our federal and state partners to understand what happened to make sure this doesn’t happen again.”
The National Transportation Safety Board will be on the scene for three to five days, a spokesperson told GBH News.
According to the MBTA, the wheels of the lead trolley came off the tracks, causing one car to derail. Most of the passengers self-evacuated and walked toward an emergency exit in the track area. Seven riders were taken to medical facilities with minor injuries.
MBTA Chief Operating Officer Ryan Coholan said during a Tuesday evening news conference that a preliminary investigation had ruled out any problems with the track, and they were focusing the investigation on “human factors.”
“Obviously, trolley operators are expected to follow operating rules, speed limit compliance and every other policy that we have in place here at the end of the day,” he said.
The NTSB said its investigation will look into “the human, machine and the operating environment.” A spokesperson said “there doesn’t appear to be any impact to foreign objects or other equipment, however it is still under investigation.”
As part of the investigation, the NTSB will gather information from image recorders and other resources. Witnesses to the accident or those who have surveillance video or other information that could be relevant to the investigation are asked to contact the NTSB at witness@ntsb.gov.
A preliminary report will be available within 30 days.
