"Big Mallard Engine going toward Pass at Red Cliff Ball Park, Colo 1917" from Alda Borah. (1919 is crossed out, replaced with 1917.) Trains of all kinds had trouble with Colorado mountain passes, eventually leading to the elimination of many routes over and through the the Rockies. Mallard engines were steam-powered locomotives developed in Europe and later versions hold the speed record for this category of engine. Alda was concerned about the...