Damage to the lines from both natural disasters and sabotage exerted great financial pressure on the company, and in 1932 Spreckels' heirs sold their interests in the railroad to the Southern Pacific, which changed the name to San Diego & Arizona Eastern Railway (SD&AE).

[1] The first through SD&A passenger train left Campo on the morning of November 30, and made the full run from El Centro to San Diego's downtown union station, Santa Fe Depot, for the official opening of the line on December 1, 1919.

East of Campo the road traveled through Clover Flats, across the Coast Range (elevation 3,660 feet), then descended through the breathtaking but treacherous Carrizo Gorge, the builders' most significant obstacle.

[2] Though the SD&A line ended in Seeley, trackage rights gave the railroad the ability to run trains as far east as El Centro and as far south as Calexico.

In 1932, financial difficulties forced Spreckels' heirs to sell their interests in the firm for $2.8 million to the Southern Pacific, which renamed the railroad the San Diego and Arizona Eastern Railway (SD&AE).