Right about the time that diesel locomotives were gaining ground on the older steam locomotives, some railroads redesigned their steam engines. By streamlining their design, the railroads hoped to keep the steam engines running. In some cases, the re-design was made so that the older steam engines would match the look of the diesel locomotives. In others, doubts about the power that could be obtained from diesel engines was the reason. For whatever reason, the result was a collision between traditional engineering design and the leading art movement of the time, Art Deco, to create some amazing examples of railway design.
A description of all that the Art Deco Movement encompasses would take much more than a single blog post. (See the Wikipedia article for a good introduction though.) Suffice to say that Art Deco is in a way a reaction to the earlier movement, Art Nouveau. While Art Nouveau features themes from nature and sinuous curving design elements, Art Deco encompasses more severe geometric forms. Art Deco’s features celebrate the exuberance of the future and its new technologies. One word that is often used to describe Art Deco is streamlined, and that is the exact reason for the redesign of steam engines in the late 1930s: to make them look fast and luxurious. Ironically, little if any performance improvements were realized as the additional weight of the streamlining offset any advantage in lowering wind resistance.