(AP) - Federal safety investigators in Midland say a parade float carrying wounded veterans apparently disregarded warning signals when it pulled onto the railroad tracks, just seconds before it was struck by a train. Four of the Iraq and Afghanistan war veterans were killed and 16 were injured. National Transportation Safety Board member Mark Rosekind said the warning lights and bells had been activated 20 seconds before the float crossed the tracks. The NTSB Saturday released a timeline of the deadly accident, reconstructed from the train's audio recording, and from video cameras from the train and a sheriff's vehicle. Investigators have not yet talked to the driver of the truck that was pulling the parade float.