Despite the size of this brochure–9″x12″ unfolding to 18″x36″–and the centennial event for which it was published, it is far from a complete history of Union Pacific locomotives. Only one-third of one side depicts and describes steam locomotives, showing just three: a 4-4-0 American class, a 4-12-2 Union Pacific class, and a 4-8-8-4 Big Boy class.
The other side shows Diesels, with special emphasis on the Centennial class 6900s. Beyond that, it shows just four: the General Motors DD-35A, GP-38-2, and SD-40-2, plus General Electric’s U30C. In short, the emphasis was on the most modern power found on the railroad, not on its history.