The El Capitan was the only all-coach or "chair car" (non-Pullman sleeper) to operate on the Santa Fe main line between Chicago and Los Angeles on the same fast schedule as the railroad's premier all-Pullman Super Chief.

The El Capitan debuted on February 22, 1938, on a twice-weekly schedule, using two five-car sets of streamlined equipment built by the Budd Company.

Originally conceived as the Economy Chief, the name 'El Capitan' was chosen to commemorate the Spanish conquistadors; it competed for passenger traffic with Union Pacific's Challenger.

Unique in charging an extra fare despite being a coach train, it pioneered such features as "RideMaster" seats optimized for sleeping.

Together with the Super Chief on even-numbered days, the two trains formed what the Santa Fe billed as "the first and only daily ⁠39+3/4⁠ hour service between Chicago and California".

[6] In 1948 the Santa Fe received additional equipment which permitted the Super Chief and El Capitan to start operating daily; the new schedules went into effect on February 29.

These were soon given to the Chief (another AT&SF Chicago-to-Los Angeles special), and replaced by new double-decker "Hi-Level" chair cars (coaches) developed by Budd and the railroad in 1954–1956.

Many Amtrak trains used a combination of refurbished former Santa Fe Hi-Level cars with newer Superliner railcars until the early 2000s.

[15] Between 1946 and 1948 the Santa Fe increased the length of the El Capitan and added new cars built during and after World War II.