news correspondent ayman mohyeldin is there. what's the latest in philly? >> reporter: the scene behind me still remains very active. we've seen some oversized trucks arrive an indication perhaps that they're prepare to go move some of those cars. we know from yesterday the ntsb says it has released the tracks back to amtrak so they can begin repairing them but they will continue the investigation by moving the cars to a secure location. the word you're hearing from ntsb officials over and over again is time line. they're trying to establish the time line for two important event events. one the time it left the train station to the time of the derailment, and also the time line of the engineer and what his-was like hflife was like the past 24 hours. we're hearing the investigation is ongoing. as a result of the train reaching about 106 miles per hour in a turn that was meant to be only about 50 miles that's broke double the speed that he was authorized to go around that curve. they're also collecting data