https://youtu.be/y6r-FzXM3CE TRACK: 1 THIS MORNING - INVESTIGATORS TRYING TO FIND THE CAUSE OF THIS DRAMATIC BRIDGE COLLAPSE IN PITTSBURGH SOT - DENNIS COLLINS, NTSB INVESTIGATOR: We're looking for indications of where it began. // signs of stress in the materials, signs of fracture, signs of deterioration. TRACK: 2 - COMBING THROUGH WHAT’S LEFT AT THE SCENE AFTER FRIDAY'S COLLAPSE LEFT …