BOSTON (CBS) ? The MBTA has released video showing the moment of impact when the two Green Line trains collided at Boylston Station Thursday.

The video shows at least one passenger catapulted out the door when the collision happens.

Investigators probing the cause of Thursday?s crash have ruled out mechanical and infrastructure failure.

They are looking at the possibility of operator error at this point. One of the trains was parked on the outbound tracks when the other struck it from behind.

Officials say there was nothing to indicate that drugs or alcohol played any role in the crash. They also say they do not believe the conductor in the moving train was using a cell phone. They are looking at the possibility of whether that driver may have been distracted.

The conductor, who had a previously flawless record, has been placed on paid leave during the investigation.

Three dozen people were hurt when the two trains collided just before noon Thursday.

At the time, MBTA spokesperson Joe Pesaturo described the crash as ?low impact.?