ELLICOTT CITY, Md. (AP) - They were seemingly ordinary tweets from two friends hanging out on a railroad bridge in their hometown, enjoying one last summer night together before heading back to college.
"Drinking on top of the Ellicott City sign," read one. "Looking down on old ec," read another. Accompanying photos showed their view from the bridge and their bare feet, one with painted blue toenails, dangling over the edge. "Levitating," read another tweet.
Minutes after the messages were sent, a CSX freight train loaded with coal barreled down the tracks and derailed, killing the 19-year-old women and toppling railcars and coal on the streets below.
Investigators were still trying to figure out what caused the derailment. Witnesses heard squealing brakes and a thunderous crash around midnight Monday.
It wasn't clear whether the women's presence on the tracks had anything to do with the derailment. They were sitting on the edge of the bridge as the train passed a few feet behind them, Howard County police said, and their bodies were found buried under coal. Authorities said they needed to do autopsies before their cause of death could be determined.
Killed were Elizabeth Conway Nass, a student at James Madison University in Virginia and Rose Louese Mayr, a nursing student at the University of Delaware.
The railroad is easily accessible from the picturesque downtown of Ellicott City, and generations of young people have played and partied along the tracks. The railroad was completed in 1830 and crosses over Main Street in the city's historic district, following the route of the nation's first commercial railroad, according to the Baltimore & Ohio Railroad Museum.
"We grew up running on those tracks," said Ellicott City native Bridgette Hammond, 25. "It's actually really beautiful up there."
Nass and Mayr were on the dance team at Mt. Hebron High School in Ellicott City and planned to finish college in 2014, according to friends and their Facebook pages.
The pictures and tweets from Mayr were no longer publicly available Tuesday afternoon, but friends confirmed they were hers and police said they were aware of the posts and looking into them.
Jill Farrell, who lives across the street from the tracks, said she heard what sounded liked squealing brakes and then a crash, followed by silence.
Jim Southworth, investigator in charge for the NTSB, declined to speculate on a possible cause. He said the brakes were applied automatically when an airline used to pressurize the braking system was disconnected. He did not say what role, if any, the brakes may have played in the derailment.
"This will be a very wide-range investigation. We will look into the maintenance of the track, the maintenance of the equipment, the maintenance of the locomotive - everything you can think of," he said.
The crew of three - an engineer, a conductor and an engineer trainee - didn't see or feel anything unusual before the crash, Southworth said. They were not injured.
The train was equipped with video recording devices that investigators will review to help them determine what happened. It was going about 25 miles per hour but Southworth would not say whether that was an appropriate speed limit for the area.
CSX spokesman Bob Sullivan said the train was traveling from Grafton, W.Va., to Baltimore. It had two locomotives, was 3,000 feet long and weighed 9,000 tons, he said. The first 21 cars of the 80-car train derailed.