From 'SP motive power finale, 1996'
"On Dec. 7, 1900, the Rock Island commenced construction toward Santa Rosa, NM. The construction started at 3 places, Liberal [KS], Texhoma, and Dalhart [TX]... the RI finally completed the line tp Santa Rosa, NM on Dec 25, 1901 ... [where] it met with the EP&NE (El Paso and Northeastern). "
(The book goes on to say how this line became part of the Golden State line, which ran from Topeka, KS to El Paso, TX and how the SP bought out another RR which owned part of the line.)
"So, for the first 50 years (ca 1910 -1960), the Golden State was instrumental in the progress of the SP and RI. Through traffic of lumber, auto parts, perishables and finished autos moved over this line bypassing a more circuitous route via SSW."
The only photo of RI equipment on this track is from 1976. It shows 6 locos (definetly a hot-shot) pulling mixed freight of boxcars, covered 3 and 4 bay hoppers and 60-80' TOFC cars.