Built for the Denver, South Park, & Pacific Railroad and numbered 51. It was the first locomotive purchased. It served on many narrow-gauge lines. Denver, South Park & Pacific Line Railroad was competing with the Denver & Rio Grande to build a line to Leadville in 1880, the same year Union Pacific purchased the line, even though this railroad operated independently. The fleet was renumbered for the Union Pacific's number system. Denver, South Park, & Leadville #51 was renumbered #191. In 1889, the line went bankrupt and was taken over by the Denver, Leadville, & Gunnison Railway. In 1899, Colorado & Southern had newer locomotives and less business. Colorado & Southern #191 was sold. The Edward Hines Lumber Company in Wisconsin used the locomotive for hauling timber to the sawmill and renumbered it seven. In 1905, the locomotive was sold again to the Robins Railroad in Rhinelander when the Edward Hines Lumber Company went out of business. In 1919, the Robins Railroad was bought out, and #7 was included with the sale to the Thunder Lake Railroad Company until 1932. This locomotive was on display at the Rhinelander Logging Museum. It sat at this location until the 1970s, when the Colorado Railroad Museum had a deal with the Rhinelander Logging Museum that the Colorado Railroad Museum needed to find an appropriate locomotive for the Rhinelander Logging Museum. So, they found Thunder Lake Lumber #5 and got #7 sold to its current location. The tender was replaced, and the locomotive was displayed once again as Denver, Leadville, & Gunnison #191.