Union Pacific switch engine No. 4455 was built by Lima Locomotive Works in October, 1920. During the late 1930s and 1940s it was assigned as the Denver Union Terminal switcher, making up and breaking down passenger train consists between the depot and the UP’s coach yard at 23rd Street.
In 1928, the Monolith Portland Cement Company of Laramie, Wyoming, built a rail line to connect their stone quarry with a newly built cement plant, establishing the Laramie Valley Railway.
A series of former UP 0-6-0 switch engines were the only motive power on the Laramie Valley line. Number 4361, a step-sister of the 4455, was purchased by the company in 1931. It operated successfully though World War II with minor repairs handled by the Union Pacific shops in Laramie or Cheyenne. By 1949, however, its grates were burned out and no replacements were available. New ones couldn’t be cast as the forms had been thrown away. The “steam age” was, in fact, winding down on the major railroads. So, the Laramie Valley Railway purchased the 4455 from the UP in 1949 and operated it until 1970, when it was replaced by a diesel.
0-6-0 No. 4455 was donated to the Colorado Railroad Museum by the Monolith Portland Cement Company and Union Pacific in September, 1972 and was moved, along with Colorado & Southern rotary snow plow No. 99201, to a short spur track of the Burlington Northern across West 44th Avenue from the museum. This spur had been built in 1963 when Chicago, Burlington & Quincy 4-8-4 steam locomotive No. 5629 was moved into the museum. The spur was left in place, but the connections to the BNSF and the museum were removed.
This temporary track would be the home for the rotary, the 0-6-0 and a standard gauge tank car for the next 35 years. Finally, In January, 2008, the rotary snow plow, its tender, and the 0-6-0 switcher were trucked across the street to the museum and placed on newly-laid display track as welcome and now accessible additions to our exhibit collection.