Volume 37 covers the Union Pacific Challengers in the following groups: UP #3975-3999 (1943 series), and #3700-3717 (oil fuel). This series of books covers all classes of steam locomotives of the UPRR and its subsidiaries. Each book is 80 pages in 11 x 8.5 horizontal format, printed on 100 lb. enamel stock and is a softcover. Each volume contains 77 quality photographs.
Supporting technical data is included for the time the photograph was taken. The books present a wide variety of photographic views that show locomotives during various eras, the various lettering and paint schemes, changes in appearance, with various tenders, as well as both sides of locomotives.
Photographs were taken by noted photographers G.M. Best, R.H. Kindig, Don Roberts, R.J. Foster, Francis Gschwind, John Conant, Stan Kistler, W.O. Gibson, Art Peterson, Art Stensvad, Lou Schmitz, Jim Ehernberger, Dave Martindell, and others. Union Pacific Historical Society, softcover, 80 pages, 11 x 8.5 x .25 in., Black-and-White photographs with captions.