The San Francisco Zephyr was the name adopted in June 1972 for the Amtrak

Amtrak

The National Railroad Passenger Corporation, doing business as Amtrak , is a government-owned corporation that was organized on May 1, 1971, to provide intercity passenger train service in the United States. "Amtrak" is a portmanteau of the words "America" and "track". It is headquartered at Union...

 passenger train between Chicago, Illinois

Chicago

Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...

 and the San Francisco Bay Area

San Francisco Bay Area

The San Francisco Bay Area, commonly known as the Bay Area, is a populated region that surrounds the San Francisco and San Pablo estuaries in Northern California. The region encompasses metropolitan areas of San Francisco, Oakland, and San Jose, along with smaller urban and rural areas...

 in California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

. Previously Amtrak had called it the City of San Francisco

City of San Francisco

The City of San Francisco was a streamlined passenger train operated jointly by the Chicago and North Western Railway, the Southern Pacific Railroad, and the Union Pacific Railroad...

 on the tri-weekly run west of Denver and Denver Zephyr

Denver Zephyr

The Denver Zephyr was a passenger train operated by the Chicago, Burlington and Quincy Railroad between Chicago, Illinois, and Denver, Colorado...

 on the daily run between Denver and Chicago. (The refusal of the Denver and Rio Grande Western Railroad

Denver and Rio Grande Western Railroad

The Denver & Rio Grande Western Railroad , often shortened to Rio Grande or D&RGW, formerly the Denver & Rio Grande Railroad, is a defunct U.S. railroad company. The railroad started as a narrow gauge line running south from Denver, Colorado in 1870; however, served mainly as a transcontinental...

 to join Amtrak in 1971 had required a routing through Wyoming

Wyoming

Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...

, avoiding the California Zephyr

California Zephyr

The California Zephyr is a long passenger train route operated by Amtrak in the midwestern and western United States.It runs from Chicago, Illinois, in the east to Emeryville, California, in the west, passing through the states of Illinois, Iowa, Nebraska, Colorado, Utah, Nevada, and California...

s traditional run between Denver and Salt Lake City, Utah

Salt Lake City, Utah

Salt Lake City is the capital and the most populous city of the U.S. state of Utah. The name of the city is often shortened to Salt Lake or SLC. With a population of 186,440 as of the 2010 Census, the city lies in the Salt Lake City metropolitan area, which has a total population of 1,124,197...

.) For passengers wanting to use the Rio Grande's service and continue on Amtrak, the timing of the trains was coordinated to facilitate a connection in Ogden

Ogden, Utah

Ogden is a city in Weber County, Utah, United States. Ogden serves as the county seat of Weber County. The population was 82,825 according to the 2010 Census. The city served as a major railway hub through much of its history, and still handles a great deal of freight rail traffic which makes it a...

 (but not Denver) with the D&RGW's Rio Grande Zephyr

Rio Grande Zephyr

The Rio Grande Zephyr was a passenger train operated by Denver and Rio Grande Western Railroad between Denver, Colorado and Ogden, Utah in the Western United States. It operated from 1970 until 1983...

.

In 1983 the D&RGW reversed its earlier opposition and elected to join Amtrak, citing increasing losses in passenger operations. Amtrak re-routed the San Francisco Zephyr over the D&RGW's main line between Denver and Salt Lake City, Utah

Salt Lake City, Utah

Salt Lake City is the capital and the most populous city of the U.S. state of Utah. The name of the city is often shortened to Salt Lake or SLC. With a population of 186,440 as of the 2010 Census, the city lies in the Salt Lake City metropolitan area, which has a total population of 1,124,197...

, which was its original preference in 1971. The change was initially scheduled for April 25, but a mudslide at Thistle, Utah

Thistle, Utah

Thistle is a ghost town in Utah County, Utah, United States, about southeast of Salt Lake City. During the era of steam locomotives, the town's primary industry was servicing trains for the Denver and Rio Grande Western Railroad...

 closed the D&RGW's main line and delayed the change until July 16. With the change of route, Amtrak renamed the train California Zephyr

California Zephyr

The California Zephyr is a long passenger train route operated by Amtrak in the midwestern and western United States.It runs from Chicago, Illinois, in the east to Emeryville, California, in the west, passing through the states of Illinois, Iowa, Nebraska, Colorado, Utah, Nevada, and California...

.