leave the scene. ntsb will begin by mapping the scene usually with a 3-d scanner to produce a complete 3-d representation of the wreckage as it currently exists. then you have a number of functional teams from fra that will each begin to do their own work in unison. you have human factors group. you have a track group. you have a signal group. you also have an equipment group. they will all begin doing their own thing in unison to try and rule in or rule out certain potential aspects of causation. robert halstead thank you for your insight. it was so helpful. again, we re expecting this news conference with philadelphia s mayor to begin at any moment. i got to take a break. i ll be right back with more in the newsroom. mayo, corn dogs. you are so out of here! ahh. the complete balanced nutrition of great tasting ensure. with nine grams of protein. and 26 vitamins and minerals. and now with. .twice as much vitamin