Scaling from the photo, I get a wheelbase of 6'-9". Like I said, seems pretty long for a freight car.
I think built-up arch bar trucks were outlawed in interchange between 1938 and 1941.
It could be argued that this car, which I take to be UP, is on home road tracks, and not interchanging. Possible. But the train itself does appear to be otherwise made up of cars that would interchange. The load looks like scrap, likely steel. If it stayed on home rails, where would the scrap be delivered?
Nevertheless, the trucks are under the car. It's carrying a load. It doesn't look like it's in MOW service.
And the trucks are interesting.
TWO interesting cars in one train in one picture. Neat. Might be more.