Visibility Zero

This episode originally aired January 28, 2019. In 1993, the Amtrak Railroad experienced the deadliest train crash in United States history when the Sunset Limited derailed while crossing Alabama's Bayou Canot bridge. Forty-seven passengers and crew were killed; scores more were injured. The clues to the cause of the crash lay etched in twisted steel and buried in the mud of the Bayou Canot.