The Federal Railroad Administration said Saturday that it had instructed
Amtrak to expand its use of a technology that would automatically stop speeding trains, an existing system that could have prevented the
derailment of an Amtrak train on Tuesday.
That train was traveling at 106 m.p.h.,or more than twice the speed limit, when it came off the tracks, possibly after being struck by some kind of projectile. Eight people were killed and more than 200 people were injured.
The technology, called automatic train control, measures the speed of a passing train and alerts the engineer if the train is moving too fast. If the engineer does not slow the train, it applies the brakes.
This system is already in place on the southbound tracks on the site where the tracks [typo, meant crash] occurred, a rail yard northeast of Center City Philadelphia called Frankford Junction. A federal official familiar with the investigation, who spoke on the condition of anonymity, said it was in place on one track and not the other because southbound trains were required to make a more dramatic deceleration on the curve there than north bound trains were.
The southbound speed limit is 110 m.p.h. before the curve, and then drops to 50 m.p.h. On the northbound side, trains must slow from 80 m.p.h. to 50 m.p.h. The federal official said that if a train took the curve at 80 m.p.h., it would not derail, so the use of the automatic stop technology there was not required.