TrainsOnTheBrain posted:Does the use, or non-use, of the Challenger cars also fall into the 'whatever was available THAT DAY' category?
Well, just my opinion but, I think those "Challenger" cars may just be fantasy. You might want to check with the Union Pacific Historical Society for exact details. From what I know of the UP mail trains from back in the steam days, the train make-up was mostly baggage cars, as all those were equipped with train line steam lines.
