Another item for the coal-in-boxcars discussion: Prior to WWII, the Truax-Traer Coal Company and others operated several open-pit lignite mines in Northwest North Dakota, some of them shipping up to 100 carloads daily. They prefered to use box cars to carry it, as lignite is a low grade of coal and tends to crumble as it dries. I don't know which direction it was shipped.