there was a fault switch or what was it? positive train control to slow it down automatically? where is that? >> it's in the process of being updated nationwide. it was federally mandated the end of 2016, they did not make the deadline and they were given an extension. i'm not sure where they're at on that. this track in philadelphia they were going 100 miles an hour that came on a 50 mile-an-hour curve so roughly double the speed you'll fly off the track. usually the most common thing is equipment failure. i was just looking up a few numbers. so far this year there's been 254 derailments and only three of them for too fast on a curve. so usually something break, but it's too early to say anything specific. unfortunately, for these