The second car of a slow-moving, six-car Red Line train derailed on Tuesday morning. A T spokesman said the car on the southbound train derailed at Broadway Station at about 9:45 a.m. "and made contact with the edge of the platform."

There were no injuries, according to T spokesman Joe Pesaturo, who said the cause was being investigated and personnel were "assessing damage to the platform's edge." Forty-seven passengers safely exited the train, Pesaturo said, and buses are replacing Red Line service between Park and JFK/UMass stations while MBTA personnel work to re-rail the train.

The MBTA also reported Tuesday morning that Orange Line trains were delayed by up to 30 minutes because of a signal problem near Wellington Station in Medford.

Chris Lisinski contributed reporting.