UPDATE, 11:10 p.m. Service has resumed with "minor" delays.
"Severe" problems on the Orange Line due to a "track" problem at State, the T advises. The track problem turned out to be a fire in an electrical cable that brought Boston firefighters to the platform. The T is going to try to re-route around the bad cable.
The Orange Line is shut between Back Bay and North Station. NO BUSTITUTION. Use the Green Line or Silver Line or walk.