Dozens of MBTA passengers were forced to walk their way out of a Green Line tunnel as part of their evening commute on Wednesday night, after a pair of trains collided and stuck together — sort of.

About 100 passengers were forced to debark and leave the train on foot when one Green Line trolley apparently rolled backward into another around 7:30 p.m. The accident halted service between Government Center and Park Street for about an hour.

According to MBTA General Manager Phil Eng, the incident in question is still being investigated and will be reported to the federal authorities as a “collision” according to their rules, but at first glance it appears the cars made contact with about the same amount of force that would be required to couple them together deliberately under normal circumstances.

“The train rolled three feet,” Eng said. “Literally if we intended to connect the two trains together, that’s what happened. It rolled three feet, the two couplers tied, and they were connected.”

Eng said, while he is “glad no one was injured,” that MBTA employees conducted a “hot wash” after-actions discussion to figure out what went wrong and to see if changes need to be made to avoid a similar occurrence in the future.

“We want to learn from these incidents. We want to continue to make sure, if there’s any rules or procedures in place, we improve them to allow the operators, the workforce, to be able to make those timely decisions in the right manner,” he said.

Gov. Maura Healey, who joined Eng as he spoke at a MBTA train terminal in Somerville, said that the incident doesn’t reflect how far the T has come since Eng took over, and that she has every confidence in the General Manager.

“I can tell you, personally, whenever something happens, whenever there’s an accident or a collision, I immediately hear from Phil,” she said.