Positive train control, or PTC, relies on Global Positioning System, wireless radio and computers to monitor train positions and automatically slow or stop trains that are in danger of colliding, derailing due to excessive speed or about to enter track where crews are working or that is otherwise off limits.
The crash happened near a switchyard about 10 miles (16 kilometers) south of Columbia where railcars hauling automobiles are loaded and unloaded. "People were screaming. I thought I was gonna die, I didn't think I was gonna survive that".
The area has three rows of tracks, and the freight train was parked on a "loading track or a side track" and "not the main track", McMaster said.
"They were fine employees", said Amtrak CEO Richard Anderson.
Board Chairman Robert Sumwalt and other investigators are on the ground in Cayce (CAY-see), where an Amtrak train slammed into a freight train early Sunday, killing a conductor and an engineer. The train was shaking and jumping, and his seat broke loose, slamming him into the row in front of him, he said. But in areas like SC, the tracks are owned by freight companies like CSX, on whom they must rely to implement that part of the technology. Other passengers were bleeding.
CSX issued a statement late Sunday afternoon, offering condolences to the families of the two men killed in the train wreck.
Epps said in a statement that two other patients are in serious condition; one is in fair condition; and one is in good condition. He said the freight train, which had no one aboard, "was on the track it was supposed to be on".
Members of Congress are calling for renewed action on positive train control. "Of course key to this investigation is learning why that switch was lined that way because the expectation is the Amtrak would be cleared and would be operating straight down" the main line, Sumwalt said. Several freight railroads have previously told the government they won't be able to meet the 2018 deadline.
"It's a awful thing to see, to understand the force involved", the governor said after touring the scene. Those who weren't hurt were taken in patrol cars to a shelter, and local businesses provided coffee and breakfast.
The Amtrak engineer sounded his horn seven seconds before the crash and applied emergency brakes three seconds before the train collided with the other locomotive at 50 miles per hour (80 kph), Sumwalt said, citing information from the passenger train's data recorder.
Engineer Michael Kempf, 54, of Savannah, Georgia, and conductor Michael Cella, 36, of Orange Park, Florida, were killed, Lexington County Coroner Margaret Fisher said.
"Any time you have anything that happens like that, you expect more fatalities". Both industry experts and rail companies say in large part it comes down to costs and the sheer size of the nation's rail system.
The wreck came just days after a chartered train for Republican members of Congress heading to a retreat collided with a garbage truck in rural Virginia, killing the truck driver. He said proven technology such as positive train control can not continue to be delayed. The passenger line says the lead engine derailed, as well as some passenger cars.