The head of the MBTA said more problems were uncovered during an investigation into a Blue Line train evacuation​ that happened on Tuesday.

An MBTA spokesperson said the train operator stopped the train after they spotted a downed wire in the tunnel.

Around 500 MBTA riders were reportedly stuck on a Blue Line train Tuesday afternoon, according to officials. The train was disabled under the Boston Harbor between Maverick and Aquarium stations, the Boston Fire Department reported. It took firefighters about an hour to evacuate the 500 people through the tunnel.