Two teens are dead after a freight train derailment in Ellicott City, Maryland.
Elizabeth Nass and Rose Mayr were sitting on the train bridge over Main Street as a CSX freighter carrying 9,000 tons of coal derailed just after midnight Tuesday.
Emergency workers found 21 cars of the 80-car train derailed or overturned.
Investigators believe the women were sitting on the edge with their backs to the side of the train as it passed when it derailed for an unknown reason.
Mayr and Nass -- students at the University of Delaware and James Madison University, respectively -- were found buried under coal, according to police.
Several cars in a nearby parking lot were crushed as some cars fell from the bridge.
The bridge runs along the main street of the historic section of downtown Ellicott City.
Cranes were used to remove the train cars from the vehicles, and the cars were searched for other possible victims, but none was found.
Mayr and Nass both tweeted about sitting on the bridge shortly before 9:00 p.m.
Mayr sent pictures of their feet dangling over the edge, and a view from the bridge.
Nearby residents heard the derailment. "I heard this tremendous noise," said one woman.
"It was the loudest I'd ever heard the train," said another, "and it was just straight screeching, and I thought to myself, 'It sounds like it's derailing.' My coffee table was just shaking, and I was like, 'OK, that's not normal.' This is awful."
It's not clear yet whether the train derailed because it was trying to avoid the girls on the bridge.
The NTSB said Tuesday afternoon that the operator did not activate the emergency brakes.
The brakes activated once the derailment began.
The train was bound for Baltimore from Grafton, West Virginia.
The National Transportation Safety Board has taken over the investigation from local authorities.
Officials said it likely will be a long investigation.
Authorities will interview the two operators on the train and check the camera and event recorder.
"It just looked like mass mayhem," said a witness. "It just looked like when I was a little kid, and I would just run the toy train off of the track, and everything went just every which way."
Nass and Mayr were graduates of Mount Hebron High School.