A list of recent major safety incidents involving the MBTA

Investigators at the scene of a crash between two Green line T trains near 971 Commonwealth Ave. in July 2021.Barry Chin/Globe Staff/file

An Orange Line train caught fire on a bridge over the Mystic River between Somerville and Medford on Thursday, sending passengers jumping out the window to avoid the smoke.

The chaotic scene was just the latest in a string of serious safety incidents involving the beleaguered Massachusetts Bay Transportation Authority in the last year. It comes as the Federal Transit Administration carries out a nearly unprecedented safety inspection of the T’s subway operations.

Here’s a timeline of recent malfunctions, derailments, and collisions that, in some instances, caused injury or death.