The City of St. Louis was a streamlined passenger train operated by the Union Pacific Railroad and the Wabash Railroad between St. Louis, Missouri, and Los Angeles, California.

The City of St. Louis began operating on June 2, 1946, between St. Louis, Missouri, and Cheyenne, Wyoming, where its cars were switched to other Union Pacific trains to continue west to the Pacific coast.

In April 1951 it became a separate train from St. Louis to Los Angeles, California, skipping Cheyenne; it still carried some cars to switch to trains to other coast cities.

The original 1946 version of the train required three consists to protect its schedule.

The consists contained a mix of heavyweight and lightweight equipment: The 10-1-1 sleeping car operated through to Portland, Oregon; cars used in this service included Balsam Fir, Douglas Fir, Inland Empire, Pinion Pine, Poudre Lake and Silver Spruce.