Tony - I think the MDC car is an attempt to model the Santa Fe 7 panel Pratt truss cars, but on their 1937 AAR box car body. But if I remember, their earlier cast metal version had a Howe truss, which might have been a little more useful on that car body.
Same car body, John, just assembled from separate cast metal pieces rather than one piece of styrene: rectangular panel roof, 4-5 Dreadnaught ends, (poorly rendered) AAR underframe. So it wasn't useful at all.
