GPS-based system could have prevented deadly train crash

South Carolina Governor Henry McMaster speaks at a press conference following a crash between an Amtrak train and CSX freight train in Cayce, SC, near Charleston Highway and Pine Ridge Road around 2:35 a.m. Sunday, Feb. 4, 20. At least two people were killed and at least 70 people were injured. (AP Photo/Jeff Blake)
Authorities investigate the scene of a fatal Amtrak train crash in Cayce, South Carolina, Sunday, Feb. 4, 2018. At least two were killed and dozens injured. (Tim Dominick/The State via AP)

CAYCE, S.C. — Federal investigators spent a second day Monday at the site of a deadly train crash in South Carolina, where an Amtrak train was mistakenly sent off a main track and down a side spur - and into a parked freight train. The ensuing crash early Sunday killed two people and injured more than 100 passengers.