The Argonaut was the Southern Pacific Railroad's secondary passenger train between New Orleans and Los Angeles via Houston, San Antonio, and El Paso, Texas; Tucson, Arizona; and Palm Springs, California.

It started in 1926 on a 61 hr 35 min schedule Los Angeles to New Orleans, five hours slower than the Sunset Limited; it was discontinued west of Houston in 1958.

[2] Unlike the first-class Sunset Limited the Argonaut was always a train for economy travel, carrying standard coaches and few standard sleepers, allowing people to travel at moderate prices but with full dining and sleeping car service.

[2] Through its life the train had olive green and black heavyweight passenger cars, pulled by steam locomotives like the GS-1 4-8-4 or MT-4 4-8-2, sometimes even a Cab Forward 4-8-8-2.

[citation needed] By its final year its route was shortened to have El Paso as its western terminus.