The Argonaut was a secondary train to the New Orleans-Los Angeles Sunset Limited that began operating in 1926. Discontinued in 1932, it was revived in 1936 and continued operating until 1958, after which it was a New Orleans-Houston train. A 1955 timetable shows that it left New Orleans about 12 hours earlier than the Sunset Limited and stopped at many more places, requiring 10 to 11 hours more to make it to Los Angeles.
Some of the Argonaut’s heavyweight coaches may have been replaced with streamlined cars in the last years of the train. But this 1958 consist suggests that the sleeping cars, at least, were still heavyweights, as “8-5” and “10-1-2” sleepers designate heavyweight types. “8-5” means 8 sections and 5 double bedrooms; “10-1-2” means 10 sections, 1 compartment, and 2 double bedrooms.