Prior to the 1971 creation of Amtrak, three competing trains ran between Chicago and the East Bay, with bus connections to San Francisco:
The California Zephyr was operated by the Chicago, Burlington and Quincy Railroad (CB&Q), Denver and Rio Grande Western Railroad (D&RGW), and Western Pacific Railroad (WP) between Chicago and Oakland along what is today called the Central Corridor and Feather River Route via Omaha, Denver, Salt Lake City and Oroville.
 Amid much fanfare and publicity, the California Zephyr was inaugurated on March 20, 1949.
It was discontinued in March 1970 – the only of the three trains not still operating when Amtrak took over service.

The City of San Francisco was operated by the Chicago, Milwaukee, St. Paul and Pacific Railroad (Milwaukee Road), Union Pacific Railroad (UP), and Southern Pacific Railroad (SP) between Chicago and Oakland on the Overland Route via Omaha, Cheyenne, Ogden and Reno.

The San Francisco Chief was operated by the Atchison, Topeka and Santa Fe Railway (AT&SF) via the more southerly Southern Transcon between Chicago and Richmond via Kansas City, Amarillo, and Bakersfield.

Railpax (renamed Amtrak in late April 1971) originally intended to revive the California Zephyr as part its original route network, using the Burlington Northern (ex-CB&Q) east of Denver, the DRG&W between Denver and Ogden, Utah, and the WP west of Ogden.
The California Zephyr route served more populated areas than the Overland Route (including Denver and Salt Lake City), ran through rural communities that lacked good highway access, and could attract passengers to its scenic routes.
However, the WP had shed the last of its money-losing passenger service with the end of the California Zephyr, and it was not eligible to participate in Amtrak's formation.
On April 12, 1971, the WP refused to cooperate with Railpax, and the SP route between Ogden and Oakland was chosen instead.
On April 26, the D&RGW elected not to join Amtrak; the contract specified that Amtrak could later increase service, and the railroad feared that would crowd its single-track mainline that competed with the UP's double-track route.
The D&RGW chose to operate the Denver–Ogden Rio Grande Zephyr, and Amtrak scrambled to piece together a Denver–Cheyenne–Ogden routing on the UP.
Prior to the 1971 creation of Amtrak, three competing trains ran between Chicago and the East Bay, with bus connections to San Francisco:
The California Zephyr was operated by the Chicago, Burlington and Quincy Railroad (CB&Q), Denver and Rio Grande Western Railroad (D&RGW), and Western Pacific Railroad (WP) between Chicago and Oakland along what is today called the Central Corridor and Feather River Route via Omaha, Denver, Salt Lake City and Oroville.  Amid much fanfare and publicity, the California Zephyr was inaugurated on March 20, 1949. It was discontinued in March 1970 – the only of the three trains not still operating when Amtrak took over service.
The City of San Francisco was operated by the Chicago, Milwaukee, St. Paul and Pacific Railroad (Milwaukee Road), Union Pacific Railroad (UP), and Southern Pacific Railroad (SP) between Chicago and Oakland on the Overland Route via Omaha, Cheyenne, Ogden and Reno.
The San Francisco Chief was operated by the Atchison, Topeka and Santa Fe Railway (AT&SF) via the more southerly Southern Transcon between Chicago and Richmond via Kansas City, Amarillo, and Bakersfield.
Railpax (renamed Amtrak in late April 1971) originally intended to revive the California Zephyr as part its original route network, using the Burlington Northern (ex-CB&Q) east of Denver, the DRG&W between Denver and Ogden, Utah, and the WP west of Ogden. The California Zephyr route served more populated areas than the Overland Route (including Denver and Salt Lake City), ran through rural communities that lacked good highway access, and could attract passengers to its scenic routes. However, the WP had shed the last of its money-losing passenger service with the end of the California Zephyr, and it was not eligible to participate in Amtrak's formation. On April 12, 1971, the WP refused to cooperate with Railpax, and the SP route between Ogden and Oakland was chosen instead. On April 26, the D&RGW elected not to join Amtrak; the contract specified that Amtrak could later increase service, and the railroad feared that would crowd its single-track mainline that competed with the UP's double-track route. The D&RGW chose to operate the Denver–Ogden Rio Grande Zephyr, and Amtrak scrambled to piece together a Denver–Cheyenne–Ogden routing on the UP.
California Zephyr