Updated at 5:15 p.m.
The National Transportation Safety Board is looking into why a switch was turned to the wrong position, forcing an Amtrak train onto a side track, where it crashed into a parked freight train.
Train 91, traveling from New York to Miami, derailed in Cayce, S.C., about 2:45 a.m. after hitting the freight train, killing the conductor and engineer on the Amtrak train and injuring 116 passengers.
NTSB Chairman Robert Sumwalt said at a news conference Sunday afternoon that the switch was padlocked to send trains on the main line to the side track, which conductors are supposed to do when they change lines.
He says the freight train crew took the CSX train from one side track across the main line and back to another side track after unloading automobiles.
Sumwalt says investigators don't know if the signals further up the line indicated the track had been switched off the main route.
Sumwalt’s comments confirmed a statement made by South Carolina Gov. Henry McMaster earlier in the day when he said "it appears that Amtrak was on the wrong track.”
"The CSX was on the track it was supposed to be on," McMaster had said, adding, "I'm sure it will prompt a renewed conversation around the country" about train safety.
The crash happened by a rail yard about 10 miles south of Columbia, where several track spurs split off for freight cars to be unloaded. Authorities said they haven't determined if both trains were moving at the time.
The Amtrak train's lead engine and some of the passenger cars derailed, Amtrak said. TV footage showed the locomotive on its side, its front crumpled. The company said about 139 passengers and eight crew members were aboard.
"The first engine of the freight train, of course, was torn up," McMaster after visiting the accident site Sunday morning, "and the single engine of the passenger train, the Amtrak train, was barely recognizable."
The National Transportation Safety Board says it will conduct an investigation into the collision.
The Red Cross has set up a shelter for passengers at Pine Ridge Middle School. The facility had received about 60 people as of late Sunday morning, as Amtrak passengers who were treated at Columbia-area shelters came to the shelter.
“Remarkably, they are in good spirits, given what they went through this morning,” said Cuthbert Langley, communications director for the South Carolina Region of the Red Cross. “Our goal as the Red Cross is to be there with hope, comfort and care for them and have conversations with them,” Langley added, “so they can begin the process of healing from this.”
Those looking for information about passengers can call the Amtrak information line at 800-523-9101.
Amtrak officials worked to gather luggage and other belongings and line up buses to take passengers on to their destinations. Those who weren't hurt were taken in patrol cars to a shelter, and local businesses provided coffee and breakfast.
"We know they are shaken up quite a bit. We know this is like nothing else they have ever been through. So we wanted to get them out of the cold, get them out of the weather — get them to a warm place," sheriff's spokesman Adam Myrick said.
Buses also are being provided to allow uninjured passengers to continue to their destination.
The crash came less than a week after at least one person died when an Amtrak train carrying Republican members of Congress "came into contact with a truck that was on the tracks" in Crozet, Va. near Charlottesville. The train was en route from Washington, D.C. to The Greenbrier Resort in White Sulphur Springs, W.Va., for a retreat.
In December, Amtrak Train 501, traveling from Seattle to Portland, derailed in Washington state, leaving three people dead and dozens injured and part of the train dangling over an overpass. Officials said it was traveling at 80 mph in a 30 mph zone. The train was carrying 77 passengers and seven crew members.
If the Amtrak - CSX train collision in Cayce, S.C. affected you directly, or if you know someone who was a passenger on the train, WFAE News would like to speak with you. Please contact reporter Alex Olgin at AOlgin@wfae.org
This story will be updated throughout the day.