Commuter train service was suspended for hours on part of the Lowell Line after a drill equipment malfunction that blocked a track in Somerville, the MBTA said.
Shuttle bus service was set up to replace trains between North Station and Anderson/Woburn. The diversion was caused by a drill rig failing while working on the Green Line extension project, according to the MBTA. It broke down near the commuter train tracks.
Normal service resumed about 7:15 p.m., according to the MBTA. There were still residual delays.
"Thank you for patience while we removed the rig from the area," the agency tweeted.
Detours involved buses from the Orange Line's Wellington Station and a network of shuttle buses.