The MBTA restored Green Line service late Wednesday morning after an electrical fire at Arlington station shut down portions of the service.
According to the Boston Fire Department, the station was shut down because of smoking electrical wires.
"The power had to be shut down to de-energize the smoldering cable. This caused the closing and evacuation of Arlington & Copley," fire officials wrote on the department's official Twitter account.
The offending cable was identified just before 10 a.m., according to the fire department.
The evacuation and shut down affected all Green Line branches. And an unrelated incident on the Red line further complicated the morning commute during one of the coldest days of the year.
MBTA Green Line service was running again as of 11 a.m. on Wednesday.