The Zephyrette was a tri-weekly train consisting of a Budd Rail Diesel Car (RDC) run by the Western Pacific Railroad between Oakland, California, and Salt Lake City from 1950 to 1960. Covering 924 miles (1,487 km), it was the longest RDC service in the United States. The successor to the Western Pacific's Royal Gorge as a secondary supplement to the California Zephyr, the Zephyrette began service on September 15, 1950. Both the existence and western terminus of the route were shaped by the stipulations of regulatory agencies, while the two RDCs the railroad purchased for the train were substantially modified before entering revenue service.