(DuPont, WA) -- The National Transportation Safety Board says inadequate planning, insufficient crew training, excessive speed and human error are to blame for the deadly December 2017 Amtrak Cascades derailment. Three people were killed and dozens were injured when the Portland-bound train derailed on the new Point Defiance Bypass rail route between Tacoma and Nisqually. The Board said Tuesday that Sound Transit, the owner of the route, should have required Positive Train Control and Amtrak didn't adequately train the train's engineer. It also said the state Department of Transportation rushed the bypass project. The NTSB has made 26 safety recommendations. DOT says it will review them before reopening the bypass.