The Denver, South Park and Pacific Railroad was incorporated in Colorado Territory on June 16, 1873. This company constructed the lines from Denver to Leadville and Gunnison and also became controlled by the UP.
The DSP&P was sold at foreclosure to The Denver, Leadville & Gunnison Railway which was incorporated in Colorado on July 17, 1889, on July 17, 1889. The DL&G became part of the UP receivership on October 13, 1893.
The Denver, Leadville & Gunnison was acquired by The Colorado and Southern Railway on December 28, 1898. The Colorado and Southern Railway was an independent Company until control of the C&S was acquired by the CB&Q in 1908.
From that time on, the C&S had to march to Chicago’s tune and the 3′ gauge main line began disappearing, the first segment in 1910 with the closure of the Alpine Tunnel and the last segment on August 25, 1943 with the conversion to Standard Gauge of the Leadville to Climax branch.