DUPONT, Wash. (AP) — The Amtrak train that plunged off an overpass south of Seattle, killing at least three people, was hurtling 50 mph over the speed limit when it jumped the track, federal investigators say. Bella Dinh-Zarr, a National Transportation Safety Board member, said late Monday that the data recorder in the rear locomotive showed the train was going 80 mph in a 30 mph zone when it derailed along a curve, spilling some of its cars onto an interstate highway below. Dinh-Zarr said it is not yet known what caused the train to run off the rails and too early to say why it was going so fast.