The Carson and Colorado Railroad was chartered in 1880 to connect with the Virginia and Truckee at Mound House, Nevada, near Carson City. The line was built to three foot gauge running south to tap the mineral resources of southern Nevada. By 1883, the line reached its full extent, crossing into California and the Owens River valley as far as Keeler, California.In 1900, the line became a subsidiary of the Southern Pacific. The SP standard gauged the northern end but in the south, retained the 3 foot gauge. When the line was severed in Nevada, the SP constructed a standard gauge line from Mojave to connect with the now-isolated narrow gauge. Known as the "Jawbone Branch", it interchanged with the narrow gauge at Owenyo, California. By 1910, the line was fully integrated into the Southern Pacific. The SP then referred the narrow gauge as the Keeler Branch. Since no rail to rail connection was available, loads had to be transferred between narrow gauge and standard gauge cars.