Upon Southern Pacific Railroad's merger with Union Pacific in 1996, less than 25% of the route was double-tracked.[2] Efforts to expand double-trackage were ongoing as of the late 2000s and early 2010s,[3] with over seventy percent of the route having two tracks by 2012.[2]
Usage
The line is primarily used for freight by the Union Pacific. BNSF shares ownership of the Lafayette Subdivision.[4] By 2007, 45 trains daily were operating through Maricopa, Arizona.[3] The AmtrakSunset Limited operates three round-trips weekly over the entirety of the route with the Texas Eagle attached between San Antonio and Los Angeles.