Liza,
NONE of it comes from the Engineer's interview with NTSB. That is absolutely false. The Engineer still maintains that he has no memory, at least as of the last NTSB press conference. The information / mention came from an assistance Conductor on board the train who was working in the dining car and heard a radio conversation between the Amtrak Engineer and the Engineer of a nearby SEPTA train which was, in fact, struck by an object about 10-12 minutes prior near the same location and the heard her Engineer state that his train had just been struck just before the accident happened. The time frame of that, according to the NTSB, sits squarely in the block of time the Engineer does not remember and the NTSB stated that a break in the Amtrak windshield looks like the break in the SEPTA windshield and the FBI has been called in to investigate that and an interview will be conducted with the SEPTA Engineer.
To suggest that it is a fabrication at this point is, at very best, ignorant of the NTSB's own statements.