This is the oldest locomotive in Colorado. It was built by the Baldwin Locomotive Works in January, 1880, as Denver, South Park & Pacific number 51, and renumbered 191 in 1885. In 1889, it went to the Denver, Leadville and Gunnison. The Colorado & Southern took possession of the engine in 1899 and numbered it 31. In 1902, it was sold to the Washburn & Northwestern in Wisconsin, and finally went to the Thunder Lake Lumber Company, also in Wisconsin, for whom it wore the number 7, in 1905. It was placed on display at the Rhinelander Logging Museum and American Smelting & Refining Company in September of 1932.
The Colorado Railroad Museum acquired the engine in 1973 through an exchange with Rhinelander for another Consolidation which the museum had purchased in order to facilitate the trade.
It was never reboilered in the 1920s, when the ICC dictated that engines with wrought iron boilers either had to be upgraded to steel boilers or scrapped, so it can never be returned to service. It has 37 inch drivers, and retains its original link-and-pin couplers.