Later that morning, the train was halted in the middle of a rush-hour trip from Worcester to Boston because of a problem with the damaged plow, delaying hundreds of riders.

The train was damaged in the early morning of Nov. 4 when it struck a barrier at low speed, with no passengers on board. But workers for Keolis Commuter Services, which runs the commuter rail system, failed to report the accident, and the train returned to regular service.

The commuter rail train involved in an unreported accident earlier this month was returned to regular service before the front-end damage was discovered, transit officials acknowledged Tuesday, a safety lapse that could have endangered passengers on one of the MBTA’s busiest commuter lines.


A day after the week-old accident was publicly disclosed, transit officials confirmed that Federal Railroad Administration investigators are reviewing the incident. Leslie Aun, a Keolis spokeswoman, said the workers involved had been placed on leave, pending results of an investigation.

On Monday, Ron Nickle, chief safety officer of the Massachusetts Bay Transportation Authority, told the agency’s oversight board about the incident. But Nickle, who likened the accident to a fatal New Jersey commuter rail crash in September, did not tell the board that the damaged train was used by passengers the next day. According to his report, the Nov. 4 accident caused damage to the train’s plow — the issue that caused an engineer to remove the train from service.

Leslie Aun, a Keolis spokeswoman, said the engineer removed the train from the line as a “precautionary issue.” Keolis workers, except for those who failed to report the accident, were previously unaware of the damage, she said.

“While the incident remains under investigation, we do not believe passengers were in danger,” she wrote in an e-mail.


The accident went unreported because of an “apparent miscommunication,” Aun said. The conductor mistakenly believed the engineer had already informed officials, she said.

MBTA officials have touted their willingness to discuss problems openly but have come under criticism for failing to promptly disclose safety and service issues. On Monday, board member Steven Poftak said he only learned about the accident at the public meeting, and the Globe reported last month that officials did not publicly reveal an audit showing an increase in derailments until almost a year later.

Aun had previously refused to say how Keolis managers learned about the unreported accident. But after further questions from the Globe, Aun said it came to light when an engineer discovered a problem with the train while it was in service.

The 6:30 a.m. train had traveled through four stops that morning when the problem arose. After the train passed the Ashland Station, the engineer “heard a noise that caused him to stop the train and conduct a visual inspection,” she wrote in an e-mail.

Duy Nguyen, a commuter who was on the train that morning, said it sounded as if the train struck something, though Keolis officials said the train did not hit anything.

“The front car rattled, and there was a hissing sound that we could hear from outside the car,” he said.

The engineer determined the plow had been damaged, Aun said, but didn’t know if something had struck the train. It was taken out of service as a precaution, and riders were delayed more than 20 minutes as they switched trains in Framingham.


Workers discovered the mishap after reviewing security tape from the train, which showed the control car hitting the post at South Station.

Joe Pesaturo, an MBTA spokesman, wrote in an e-mail that the agency had “expressed its concern about this incident in no uncertain terms, and (Keolis) has made it clear that it is treating this situation with the level of seriousness it deserves.” He declined to say why the MBTA had not told board members or the public about how the damaged train had been put back into service.

MBTA officials declined to provide documents related to the accident, saying it remains under investigation.

When told that the damaged train had been used the next morning, Poftak renewed his call for greater transparency on safety violations.

“I think we need to come up with some systematic way of reporting major safety incidents so the board has a clear understanding of what happened and what corrective action was taken in all cases,” he said.

Nicole Dungca can be reached at nicole.dungca@globe.com. Follow her on Twitter @ndungca.