Passengers on an outbound Orange Line train busted out windows when the train filled with smoke and the doors wouldn't open shortly before 5 p.m.
WBZ reports three people were taken to the hospital for smoke inhalation.
The train driver reported a "pop" and some sparks as his train entered the station; possibly due to a motor sparking and setting trash on the tracks on fire.
Commuter-rail and Amtrak service through Back Bay was also halted. Buses that normally stop at Back Bay are being diverted to Copley Square.
The T set up shuttle-bus service between Jackson Square and Copley Square.
Uber pricing went into overdrive. And then some.
The Orange Line halt came just as the Red Line was having its own meltdown.
On Sunday, Red Line service was halted when a trash fire sent smoke into South Station.
This coming Saturday, the T is planning a drill at Alewife station involving smoke filling a subway tunnel and station.