Main East-West route, formerly the old Southern Pacific Sunset Limited route.
The Buffalo Bayou & Colorado Railroad began building west from Houston before the Civil War.
After the war it was reorganized as the Galveston, Harrisburg, & San Antonio and began building west again in 1870.
It reached San Antonio in February 1877, then in May 1881 built west again to meet the Southern Pacific Line.
The Southern Pacific built east from Los Angeles reaching Yuma in September 1877, Tucson in March 1880, and El Paso in May 1881.