It's a scale test car from the Washington Department of Agriculture who manages weights and measures state wide with the exception of a couple of counties (Spokane for one) who do their own. What I don't know is if the scale test car tests the railroad owned scales or shipper track scales. The only railroad owned scale in the Spokane area that I know of is the weigh in motion scale at Hauser Yard. (in Idaho). The last scale in Spokane was at Erie St. yard and was removed many years ago. Anyone know if there is still a scale at Kettle Falls? It's been years since I've seen one of those little stubby railroad owned scale test cars----I'm told that UP still has a couple in service, my source at BNSF says they use cars similar to the Washington State one (but he didn't know if any of the little ones were still in service.)
The little short stubby ones have fallen out of favor because they don't have air brakes, and tend to ride poorly.