The Capitol Corridor is a 168-mile (270 km) passenger train route in Northern California operated by Amtrak between San Jose, in the Bay Area, and Auburn, in the Sacramento Valley.

The Capitol Corridor Joint Powers Authority (CCJPA) is governed by a board that includes two elected representatives from each of eight counties the train travels through.

By the end of the 1930s, the SP operated five daily local round trips plus a number of long-distance trains between Oakland and Sacramento.

[2] The increasing prevalence of auto ownership and improvements in local roads meant that numerous commuters began to drive their own vehicles rather than take the train.

[4]: 140 From the 1970s to the beginning of the 1990s, three Amtrak intercity trains operated in the Bay Area: the long-distance California Zephyr (Oakland/Emeryville–Chicago) and Coast Starlight (Los Angeles–Seattle), and the regional San Joaquins (Bakersfield–Oakland).

Of the three lines, only the Coast Starlight ran between San Jose and Sacramento—once a day in each direction, and at inconvenient times (southbound early in the morning, northbound in the evening).

[8][9] The Capitols originally ran via the Coast Line from Elmhurst to Santa Clara, with no stops between Oakland and San Jose.

[15] The Capitol Corridor Vision Implementation Plan is a long-range outline of possible improvements to the service; several realignments along existing and new right-of-ways were considered and studied.

Later goals include tunneling under Jack London Square to eliminate the street-running section there, rerouting freight traffic over another right-of-way between Sacramento and Martinez, and eventual electrification of the line.

[16] The 2018 Senate Bill 1 allocated $93 million in funds for the Capitol Corridor, partially for planning the realignment to the Coast Subdivision.

[18][19] Two daily Capitol Corridor round trips, along with some Caltrain service, were planned to be extended to Salinas as part of the Monterey County Rail Extension.

[22][23] Extension east to Reno, Nevada was deemed unlikely in the Vision Implementation Plan due to heavy freight traffic over Donner Pass and lack of funding,[16] though plans for such an expansion were studied in 2022[24] with 83% of respondents indicating they would use the service if more frequent passenger rail were provided between Sacramento and Reno.

[25] Extending service to downtown San Francisco by crossing the bay is being considered as part of a proposed second Transbay Tube.

[27] It is the fourth busiest Amtrak route by ridership, surpassed only by the Northeast Regional, Acela Express, and Pacific Surfliner.

Many politicians, lobbyists, and aides live in the Bay Area and commute to their jobs in Sacramento, including those connecting to the train via Amtrak Thruway from San Francisco,[29] while workers in the Oakland, San Francisco, and Silicon Valley employment centers take the Capitol Corridor trains from their less expensive homes in Solano County and the Sacramento metropolitan area.

[32] As of October 2022, trains run as follows:[33] The Capitol Corridor is fully funded by the state through Caltrans Division of Rail and Mass Transportation (DRMT).

[36] The Charger locomotives meet EPA Tier IV emission standards and are capable of operating at 125 mph in revenue service.