WASHINGTON (Reuters) - Investigators probing the May 12 derailment of an Amtrak train in Philadelphia do not yet know whether an electronic warning device was operating or activated before the disaster, National Transportation Safety Board Chairman Christopher Hart told the U.S. Congress on Tuesday.
In prepared testimony to a House of Representatives committee, Hart also said several U.S. rail carriers will not meet an end-of-year deadline for installing a more sophisticated safety system known as Positive Train Control.
"This is disappointing," Hart said, adding the equipment would have prevented the Amtrak train from speeding up before a dangerous curve.
The derailment caused eight deaths and about 200 injuries.
(Reporting by Richard Cowan; Editing by Lisa Lambert)