know. reporter: drivers on the interstate below were injured as the train came crashing down, but none killed. dan konzelman jumped out of his car in snarled traffic and onto the train to help. we climbed underneath the train as best we could, and there was people, like, with half their bodies pinned who couldn t move and were in a lot of pain. a lot of them were screaming and moaning, but there was nothing we could do to help them really, so we just stayed with them. they re requesting all possible units. there s bodies on the freeway. when we got to the scene, it was obvious that there were some fatalities and there were a lot of injuries. reporter: chris karnes, who had been tweeting earlier, survived. the train started to wobble for a moment and then we were catapulted at the seats in front of us. and the next thing we knew, our car had crumpled. when i stepped out, i didn t really realize i was standing on another train car. reporter: the passengers were the first
reporter: what was supposed to be a celebration, the first run of newer, faster train service, tonight is a tragedy of twisted metal, with multiple passengers dead. oh, my god. that train is derailed. train derailment over the freeway. multiple patients. reporter: amtrak train 501 left seattle just after 6:00 a.m., heading toward portland. 86 passengers and crew on board. at 7:30, passenger chris karnes tweeting, wow, this train is fast. we are passing up traffic on i-5. minutes later, at 7:33 a.m., a lock motive and 12 cars careen off both sides of the overpass, down onto interstate 5, crushing vehicles below. amtrak 501. emergency. emergency. emergency. we are on the ground. reporter: the conductor radioing for help. hey guys, what happened? we were coming around the corner to take the bridge over i-5 there right north of nisqually and we went on the ground. is everybody okay? i m still figuring that out. we got cars everywhere and down onto the highway. as soon