Link21 is a multi-phased, long-range transportation program that includes close coordination with agency partners, community stakeholders, and the public through each phase of work. Planning efforts are currently focused on identifying a new underground train crossing of the San Francisco Bay that would improve existing train service, connect to other planned rail projects in the Megaregion, and provide new rail access to communities in the Bay Area.
Phase 1 Activities
Phase 1: Concept Identification builds on the foundational work established in Phase 0 with the Business Case Framework that outlines Link21 vision, goals, objectives, process, and criteria for measuring rail improvement solutions.
Current Phase 1 activities focus on exploring and assessing potential concepts for a new crossing of the San Francisco Bay as well as other key service and supporting infrastructure improvements for both the BART and Regional Rail networks. Assessment considers the Megaregion’s projected population, changing workforce needs, travel patterns, air quality and climate change impacts, and more.
This early work is critical in establishing the right projects for Link21 that build upon the significant rail investment already made throughout the Megaregion. A second train crossing of the Bay will amplify benefits to riders and communities creating a more integrated network that offers riders reliable travel options to reach their desired destination.
Concept Identification Process
At each step, the public will have the opportunity to provide input. Learn more about our concepts and how to get involved now and throughout Phase 1.
In early 2024, the Program will go to the BART and Capitol Corridor Boards of Directors with a recommendation of which train technology should go in the crossing. Concept options that include station and service improvements, and infrastructure to support those improvements, will continue to be assessed in 2024 as the Program works to identify a project to advance to Phase 2 Environmental Review. This milestone is an important first step to identifying how we can connect and improve service within the megaregional train network.
Ongoing Equitable Engagement
The Link21 Team is working directly and proactively with communities through a variety of ongoing engagement and outreach activities. In addition, we are connecting with Megaregional communities at key milestones in the technical work, where timely input is critical to decision-making. These activities include:
- Targeted activities with agency partners, elected officials, youth, tribal, and priority population communities
- Active partnerships with community-based organizations to co-create activities with their communities.
- Regular workshops with the Link21 Equity Advisory Council
- In-person and virtual events such as community and train-station tabling, briefings, and presentations
Early Environmental Activities 
Link21 is planning ahead to make sure that all future projects support and comply with state and federal environmental requirements. Initial environmental activities include data collection to identify environmental constraints and opportunities that are helping to guide the refinement of concepts. Assessment is also focused on understanding potential Environmental Justice* effects and benefits.
*Environmental Justice is the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income, with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies.
Planning Work
Planning work includes close coordination with agency partners to share and collaborate on concept options that will best serve future travel needs. Activities include:
- Ongoing concept exploration and evaluation
- Identification of potential service improvements and assessment of train technology benefits to achieve desired service
- Ridership modeling and preliminary cost estimates
What We Have Learned So Far
Through exploratory work, the Link21 Team has learned that a single two-track crossing (with either BART or Regional Rail train technology) can meet Link21 Goals and Objectives. More specifically, a single two-track crossing with associated improvements to both BART and Regional Rail systems:
- Meets projected travel demand between San Francisco and Oakland by 2050
- Improves passenger reliability and provides needed redundancy in case of a track or tunnel closure in the existing BART crossing
- Provides faster and more frequent service for both long- and short-distance trips
- Enables increased train frequency that can grow ridership
- Provides benefits to priority populations across the network in different ways
- Reduces potential future crowding in the existing BART crossing
- Supports other rail improvements/projects by connecting them to the new rail crossing
