UPDATE: Man Trapped Under Red Line Train Tuesday in Critical Condition

UPDATE, Wednesday 2:45 p.m.: MBTA spokesman Joe Pesaturo said that the man who was hit by a Red Line train Tuesday is in critical condition. Transit police are investigating the incident. Furthermore, "it remains unclear at this time why he trespassed on the tracks," Pesaturo said.

UPDATE, Tuesday, 2:15 p.m.: Red Line service has been restored.

Original post, 1:45 p.m.:

The Red Line has shut down between Harvard and Broadway stations as the public safety personnel deal with a "medical emergency" at Downtown Crossing, according to the MBTA's Twitter feed. The Boston Fire Department confirmed they were able to extricate a person who fell under a Red Line train at the station.

There's been no immediate word on the condition of the person. The Red Line was stopped so officials could switch off power to the third rail  as firefighters worked to free the trapped person , according to the Fire Department.

The T is scrambling buses to shuttle passengers while the Red Line service is stopped. The Orange Line is not affected. Travelers can stay up to date by following the T's Twitter page or the MBTA's Red Line advisory web page.