At least three people were killed and more than 75 were injured when a speeding Amtrak train derailed and plunged off an overpass in Washington State on Monday morning. Officials initially described six people as dead, but lowered that total Monday evening. Four of the hospitalized are critically injured, the Seattle Times reported. Some commuters on the highway beneath the overpass were also injured but none were killed. Thirteen of the train's 14 cars slipped off the track, some colliding with the highway below. The train was on the inaugural run of a new route between Portland and Seattle and traveling 81 miles per hour, close to its top speed at the time of the derailment. It is unknown what caused the train to leave the tracks.