northeast corridor it's so common getting hit by projectiles, that he actually protect themselves with armor in the front window. listen to robert sum walt of the ntsb. >> we are investigating the accident and have asked the fbi to come in and provide technical expertise to help us resolve and figure out what was a particular damage pattern on one of the windshields. we're investigating it at this point and asked hem to help us identify that fracture pattern. >> whether or not this was the cause of the train going 106 miles. er hour, we just don't know but the federal railway administration has ordered amtrak to install atc, automatic train control. that would alert the engineer the train's going too fast. they also asked them to put signs up for curves and signs up for speed. alex. >> adam reiss in philadelphia, thank you much. fewer americans are identifying themselves as christians. what's behind this shift? but first the amtrak crash will