CES inspected every igneous rock (granite, rhyolite, basalt, etc.) outcropping within 3 miles of the UP/SP Railroad between Los Angeles, California, and Van Horn, Texas. Outcrops were mapped in GIS using publicly available digital geological maps. Hand samples were collected from outcrops that appeared to display suitable ballast properties. Undisturbed rock samples were collected at selected locations using conventional coring equipment. Core samples were analyzed for Los Angeles (LA) abrasion, mill abrasion, bulk density, specific gravity, absorption, and silica content. Samples from superior deposits were also analyzed petrographically to determine rock type, major and minor mineralogy, the ratio of crystalline to glassy matter, crystal size distribution, porosity, mode/degree of cementation, reaction rims, and degree of foliation. The project led to the discovery of a rhyolite deposit near Sierra Blanca, Texas that was leased and put into production and became a favorite ballast source of the UP/SP Railroad.