|Snow Train Rolling Stock is significant under Criterion C in the area of Engineering, comprising excellent examples of different types of rolling stock that served on the Union Pacific Railroad system during the first half of the twentieth century. The five pieces of rolling stock possess shared historical associations as equipment built for and used by the Union Pacific Railroad or its subsidiaries during the historic period. Locomotives are the most numerous type of railroad rolling stock resource listed in the National Register of Historic Places. Snow Train Rolling Stock includes examples of underrepresented rolling stock car types. This collection of rolling stock exhibits developments in twentieth century railroading and railroad practices , including the development of all-steel car bodies, design innovations, and the repurposlng of rolling stock to new uses, such as wedge snow plows and bunk cars. As an assemblage, the rolling stock illustrates the typical arrangement and car types making up a Wyoming snow train of the 1950s. Snow trains were not preassembled, standing in readiness for heavy snow. Instead, as a weather emergency developed, trains to plow the lines were put together from available rolling stock. The locomotive of the ensemble is also significant under Criterion A In the area of Transportation for its service in Wyoming from 1947 to 1957, including powering snow trains during the blizzard of 1949. No railroad rolling stock in Wyoming is currently listed in the National Register.