The MBTA partially shut down service on the Green Line in Boston because a trolley rolled back into the trolley behind it at Park Street.

No injuries were reported after a Green Line trolley rolled backward and “hitched” onto another trolley Wednesday, according to the MBTA.

Shortly before 7:30, a stopped Green Line trolley at Park Street rolled backward and hitched to the trolley behind it, officials said.

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.