On December 18, 2017, Amtrak Cascades passenger train 501 derailed near DuPont, Washington, United States. The National Transportation Safety Board's (NTSB) final report said regional transit authority Sound Transit failed to take steps to mitigate a curve at the accident location, and inadequately trained the train engineer. The train was making the inaugural run of the Point Defiance Bypass, a new passenger rail route south of Tacoma, Washington, operated by Amtrak in partnership with state and local authorities in Oregon and Washington, on right-of-way owned and operated by Sound Transit. The bypass was intended to reduce congestion and separate passenger and freight traffic, and was designed for faster speeds and shorter travel times, saving ten minutes from Seattle to Portland compared with the previous route used by Cascades.

The Amtrak Cascades is a passenger train corridor in the Pacific Northwest, operated by Amtrak in partnership with the U.S. states of Washington and Oregon. It is named after the Cascade mountain range that the route parallels. The 467-mile (752 km) corridor runs from Vancouver, British Columbia, through Seattle, Washington, and Portland, Oregon, to Eugene, Oregon.