UPDATE at 9:20 a.m.: Looks like the power is back on and some trains are moving again, but slowly, since the signals aren't working.

9:30 a.m. Joe Pesaturo: "Power is being restored, but all lines are experiencing delays. An investigation into the cause of the outage is underway." T now advising people to not take the T.

9:50: Boston Police report the Red Line still dead due to signal problems.

1 p.m.: NECN reports the T is blaming "a private company doing routine maintenance" on the system. More to come at a 1:30 news briefing.

People stuck on trains all over the place:

Red Line.

Orange Line.

Green Line.

Blue Line:

*MAJOR* mbta fail. no power at Maverick T station. no buses. making people walk to airport to get buses. in a cab now.

No lights at Back Bay station; commuter-rail tracks almost pitch black.

Nykwil proposes the MBTA buy one million hamsters and wheels as a power supply.

Michael Femia: Maybe the T shouldn't have diverted all of its power to David Ortiz.