I'm standing by my opinion from the day after the derailment that the engineer of 188 simply lost track of where he was on the railroad: that he thought he was east of Frankford Junction, had entered 110mph territory and was accelerating appropriately when, in fact, he was still west of the junction. In my opinion, it was human error that was compounded by the fact that the existing signal system was not configured to prevent an eastbound overspeed train from entering that curve (as it was for westbound trains). My opinion, and my opinion only.