Jul 12, 2012 7:00 AM by AP
COLUMBUS, Ohio (AP) - Investigators say a train that partly derailed and exploded in Columbus, Ohio, was traveling below the speed limit before the crash, and its operators noticed no problems with the track as they approached the curve where it happened.
The National Transportation Safety Board is investigating what caused the Wednesday derailment on Norfolk Southern Corp. tracks north of downtown.
Three tank cars carrying ethanol exploded. No one on the train was hurt. Two people were injured while walking on the tracks to investigate when a second explosion occurred.
Investigators are reconstructing the rails in hopes of spotting any anomalies. The full investigation could take a year.
Board member Earl Weener says the track had been visually inspected Monday and had undergone more thorough testing in April during an annual inspection.