Jim, in the AFE stuff they refer to these cars as Hog Fuel Crates. The AFE's show various flat cars "converted to hog fuel crate". I wonder why this distinction vs. just calling them a high side gondola?
Were the dry kilns built at Bates at the time of conversion to truck haul? This would make some sense if the lumber being truck hauled was planed and kiln dryed thus reducing the weight and bulk. It would also make sense that the wood waste formerly hauled by the rr to the steam power plant was needed to produce the additional steam for the dry kilns. Rampant speculation on my part, but I have wondered this for a long time.