The story of Union Pacific's Challenger 4-6-6-4 steam locomotives from development to their final years. Illustrated with B&W photographs and extensive text.

Contents:
Ch. 1: The First Challengers;
Ch. 2: Union Pacific Influence;
Ch. 3: Passenger Assigned;
Ch. 4: Modifications 3900-3939 Early Series;
Ch. 5: Operations 3900-3939 Early Series;
Ch. 6: Jabelmann Power;
Ch. 7: Extra 3950 West;
Ch. 8: War-Time Duplicates;
Ch. 9: Last Steam Design;
Ch. 10: Modifications Later Series;
Ch. 11: Operations Later Series.

Auto-Liner, hardcover, 144 pages, standard portrait book 8 x 10 in., B&W photographs.