joining me now is former ntsb board member kitty higgins. kitty, we're hearing that the section of the track had a 50-mile-per-hour speed limit. that the train was, from initial reports, going at over 100 miles per hour. how accurately can we monitor train speeds on any given day? >> well alex, what is interesting is that this train and the asella also an amtrak train, have to follow the same rules. the asella train has something called positive train control, or automatic train stop. so that speed is monitored, and if the engineer for whatever reason, is exceeding the speed, the train will automatically stop. you've got an amtrak train in this accident that apparently did not have that feature. so it is possible through technology to monitor speed. we will know more once we get the read out of the black box. but from my perspective, that technology ought to be on every train in the northeast corridor. >> so this was a regional train. that technology to monitor speed was not on the regional train. in terms of when you hear that the train was