DUNSMUIR, Calif. — Operation of Amtrak’s Coast Starlight remains disrupted following a Sunday, March 1, derailment of a Union Pacific train at the Cantara Loop near Dunsmuir.
According to a local TV report, about 19 cars derailed Sunday evening. UP told the broadcaster today (Tuesday, March 3) that no hazardous materials were involved and cleanup was continuing. A Siskiyou News article says there were no reported injuries and has several photos of overturned grain hoppers.
Starlight operations have been disrupted since Sunday evening, with the northbound and southbound trains departing that day being turned at Sacramento, Calif., and Klamath Falls, Ore., respectively because of the closure. On Monday, both trains were canceled in their entirety; today, northbound No. 14 operated between Los Angeles and Sacramento, while southbound No. 11 was cancelled out of Seattle but will operate on Wednesday between Sacramento and LA.
— To report news or errors, contact trainsnewswire@firecrown.com.

It is a 15 degree curve, so stringlining is always a possibility. The Espee found out in the early 1990’s when a tank car of metam sodium fell into the Sacramento River.
As seen: a loaded unit grain train derailed to inside of curve. Something caused it to stringline. Leave speculation to others