CNN Forensic Files June 24, 2014 08:08:00
The tape revealed the train was traveling at 72 miles per hour and there was no brake application. whatever caused the crash, the engineer never saw it. investigators also discovered the signals on the track were green. >> the signals are controlled by a current that goes through the rail, and if the rail breaks, the signal will immediately turn red. so, the signal didn't turn red. >> the bridge was originally built in three sections. the southern section was a 165-foot steel truss bridge. the center section, a single 140-foot steel girder, was originally designed to pivot so river traffic cou...