COLUMBIA, S.C. (AP) — Federal officials are meeting to discuss what caused an Amtrak train to divert onto a side track in South Carolina last year and slam into a parked train, killing two crew members and injuring more than 100 passengers.

The National Transportation Safety Board is meeting Tuesday in Washington, D.C.

The board already determined that railway signals that would have warned the Amtrak train to stop were out because crews were installing an advanced safety system that would automatically halt the passenger train before it headed down a side track.

A CSX train crew had parked its train on the side track near Cayce a few minutes before the Amtrak roared down on it at about 50 mph (80 kph) on Feb. 4, 2018.