Question: What year did the Southern Pacific class AC-9 begin running between Alturas, CA and Nevada's fifth most populous city?
Sentence (from "Southern Pacific class AC-9"): Between 1939 and 1952, all the twelve AC-9 engines were in service between Tucumcari, New Mexico, El Paso, Texas, and Tucson, Arizona, where they mainly pulled freight trains and occasionally also passenger trains such as the "Golden State Limited".
Relevant evidence: No