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About Link21

Link21 and its Partners Will Connect Northern California 

Link21 and its partner agencies aim to better connect the BART and Regional Rail (including commuter, intercity, and high-speed rail) network in Northern California, as envisioned by the California State Rail Plan. The Program is working to identify projects that will improve our ability to move around the 21-county Northern California Megaregion by train.  

A critical step towards a better train network is the construction of a second underground train crossing of the San Francisco Bay. This crossing will enable riders access to destinations across Northern California, which includes the greater San Francisco Bay Area, the Sacramento area, the Monterey Bay area, and the Northern San Joaquin Valley. 

Link21 will result in a more connected, equitable, and accessible train network. The Program will make it more convenient for people to take BART and Regional Rail, encouraging more train travel in the Megaregion. A better train system will improve the quality of life for residents and visitors alike. Link21 will enable train service that will be:


Fast Train

RELIABLE: Depend on passenger rail to get you where you need to go.


FREQUENT: Wait less and have more travel options.

Mesh Network

CONNECTED: Enjoy quick and easy train access to home, jobs, airports, healthcare, school, sports, and entertainment.

Cloud Blowing

GOOD FOR THE ENVIRONMENT: Help improve air quality by using alternatives to driving.

Increasing Bar Chart

GOOD FOR THE ECONOMY: Benefit from a $145 billion economic boost to the Megaregion and the creation of 377,000 jobs generated by the Program (2021 estimate).


EQUITABLE: Have more passenger rail options with better access to quality jobs and affordable housing.

Link21 is sponsored by BART and Capitol Corridor with support from the California State Transportation Agency (CalSTA) and other partners.

During the Link21 program development process, BART and Capitol Corridor will work with its partners to identify and prioritize projects that are needed to create a connected train network.

Link21 Will Include a New Train Crossing of the Bay Between Oakland and San Francisco 

For decades, transportation leaders have recognized the need for a new train crossing between Oakland and San Francisco. The State Rail Plan and the Metropolitan Transportation Commission’s (MTC) 2019 Horizon initiative include a new crossing in its vision for a more connected passenger rail network in Northern California.1, 2 
The existing transbay corridor includes BART, the San Francisco-Oakland Bay Bridge, buses, and ferry service and is one of the most congested transit routes in the United States. What could be a 15-minute journey can easily turn into an hour or more due to traffic or transit disruptions. 
Link21 is planning a new train crossing of the Bay between Oakland and San Francisco. Travelers will be able to ride comfortably between the Sacramento Area and downtown San Francisco, the Northern San Joaquin Valley, the Peninsula, and the South Bay. Regional Rail riders with destinations across the Bay may be able to take a direct rail connection without transferring to a different service. 
Watch experts talk about the benefits of Link21 or read a report on how the new crossing will be a game changer for Northern California.

1California Department of Transportation (Caltrans), California State Rail Plan, 2018

2MTC, Horizon, 2019

The New Transbay Rail Crossing is critically important for the future of the Northern California Megaregion. It will literally transform the entire megaregional transportation network. I try not to use the phrase ‘game-changer,’ but that’s exactly what it is. A game-changer.

- Secretary David Kim, CalSTA in the webinar Bay Area Impact: The Megaregional Case for a New Transbay Rail Crossing


Why Link21 and Why Now?

Northern California's population is projected to reach 14.9 million by 2050. Travel demands across the Megaregion are expected to increase sharply in the coming decades. Without improving our public transportation system, traffic congestion and overcrowding will worsen, pollution will reduce air quality, transit will be strained, and economic stagnancy will diminish our quality of life.

The benefits of Link21 extend far beyond the San Francisco Bay Area and will benefit generations to come. Link21 will facilitate new connections and open up more possibilities for business and leisure travelers across Northern California.