PHILADELPHIA — Safety technology that can prevent crashes like a deadly passenger train derailment in May has been activated on Amtrak tracks between Philadelphia and New York.

Officials say the technology called Positive Train Control, or PTC, was activated over the weekend, completing the safety system along the railroad's busy Northeast Corridor. PTC was activated on the Philadelphia to Washington section a week ago, and the stretch from Boston to New Haven, Connecticut was already operational.

Investigators say the May 12 crash in Philadelphia, which killed eight people and injured about 200, could have been prevented if PTC had been in operation.

PTC uses GPS and other tracking systems to automatically stop trains in danger of derailing because they're traveling too fast, are about to collide with another train or are about to enter a work area.