City of Los Angeles service began in May 1936 using the diesel-powered custom streamliner M-10002.

It was the second of Union Pacific's diesel streamliners to the west coast, following the City of Portland that started service nearly a year earlier.

Service frequency was doubled in July 1938 with the former City of San Francisco streamliner M-10004.

The UP scored a public relations coup in the mid-1950s when the City of Los Angeles was featured in two episodes of the popular television series I Love Lucy.

Actor Ronald Reagan often traveled on this train and even did a full-page print ad for it that appeared in the National Geographic magazine.

The City of Los Angeles name has also been applied to a 48-seat diner built by the St. Louis Car Company in 1949.

[5] The second articulated trainset was replaced with an eleven car non-articulated train powered by an EMC E3 twin locomotive set in March 1939.