This mirrors the NTSB/FRA response to the MARC-Amtrak wreck at Georgetown Jct/Silver Spring on CSX in Feb 1996. The wreck occurred as far as can be determined because the engineer either never saw or failed to register/acknowledge/obey a "yellow" signal. (Despite CSX rules to radio call ALL signals,due to weather conditions there is no record of such transmissions) Instead of either insisting a new "intermediate signal" (there had been a revenue station stop after passing the alleged "yellow") the buff strength requirements were raised continuing the American exceptionalist style.
As we all know,in the WA case, there was insufficient training, and insufficient trackside warning of the speed reduction necessary for the curve. A flashing yellow to get the attention of the eng9ineer (or whatever version is compastible with other BNSF signalling protocols on that division) and severalweeks more qualifying trips would have saved the day IMHO. Doublingdown on the buff strengthdoes NOTHING to prevent mishandling the train.