I work as a conductor for UP in Oregon and when we run from Portland to Hinkle (Pendleton) we pass by the Umatilla Chemical Weapons depot. It was actually an interchange point called "Arsenal" before the switches were pulled. My question is when did the rail operations stop there, and how busy were they? The physical plant is massive, there are a couple of abandoned yards that are larger than the ones we serve in Portland, and tracks come and go every which way. Any information would be helpful.