Agency orders safety measures

The Federal Railroad Administration said Saturday that it had instructed Amtrak to expand its use of a technology that would automatically stop excessively speeding trains, an existing system that could have prevented the derailment of an Amtrak train on Tuesday.

That train was traveling at 106 mph, 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 others 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 respond, the train stops.

This system is already in place on the southbound tracks near the site where the accident occurred, a rail yard northeast of 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 northbound trains.

The southbound speed limit is 110 mph before the curve, and then drops to 50 mph. On the northbound side, trains must slow from 80 mph to 50 mph. The federal official said that if a train took the curve at 80 mph, it would not derail, so the use of the automatic stop technology there was not required.

The railroad agency also ordered Amtrak to assess all the curves on the Northeast Corridor for safety.