The line dates back to the early 1880s, when the predecessors of the D&RGW completed a narrow gauge line through the Royal Gorge, over Marshall Pass, through the Black Canyon of the Gunnison, across the Utah desert, and over Soldier Summit. It was rebuilt to standard gauge in 1890, and has since remained a through line, often serving as parts of larger networks including the Gould transcontinental system, Southern Pacific, and now the Union Pacific.