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Link21 Program Development

Planning for the Future of Train Service

For decades, rail agencies have envisioned new ways to improve Northern California’s existing train network and serve our communities. Link21 is building on a number of public mandates to bring this vision to reality.

The Link21 Team is steadily developing the Program and moving it forward. Recognized as an “anchor” program in MTC’s Plan Bay Area 2050, Link21 will help unite and support communities throughout the Megaregion.

The Link21 vision involves building a new train crossing of the Bay that will connect more communities throughout the Megaregion. A new train crossing between Oakland and San Francisco was included in two major regional funding measures: BART Measure RR (70.5% approval in 2016) and Regional Measure 3 (55% approval in 2018). Both measures presented voters with information on the new crossing and helped fund Link21. A new crossing is also included in the 2018 State Rail Plan.

We will evaluate how a second train crossing of the Bay and other improvements to the train network within Link21 can benefit the Northern California Megaregion. Improvements to the transbay corridor — and other rail improvement projects around the Megaregion — will provide cascading benefits by improving service throughout the rail network, even in locations that are far from those projects.

Building Blocks for Better Travel

The Link21 Program sponsors and partners want to deliver the greatest value for taxpayers’ investments. Here are the four foundational building blocks that are helping to shape the Link21 Program.

  • Markets: people and their travel patterns. The Link21 Team is identifying the most-promising travel markets around the Megaregion to target for train service improvements, resulting in a more optimal train network for all.
  • Service: your experience as a train rider in Northern California. Link21’s overarching goal is to transform the passenger experience. We can do that by improving train service and making our network more connected, convenient, and accessible.
  • Train Technology: the types of trains we're going to run. In the next 15 years, trains in California will be converting to zero-emission vehicles. Operators throughout California will be running modern, fast, and environmentally-friendly trains.
  • Infrastructure: the physical improvements needed for the expansion of service and markets.

Understanding travel patterns, establishing service improvements, and deciding on optimal train technology and infrastructure will guide future planning efforts. The Link21 Team has begun defining these four building blocks, but formal decisions to shape the Program still lie ahead. Link21 will continue analyzing and adding detail to these topics in the coming years. We encourage the public to provide feedback on the Program so far. 

Program Timeline

Link21 is committed to listening to and learning from our residents' lived experiences, so that we can find solutions that meet your needs. Equitable engagement and outreach are integrated throughout all phases of Program planning.

Phase 0

Program Definition

2019-2022 (Complete)

Phase 1

Project Identification

2022-2025 (We are here)

  • Preliminary Business Case
  • Concept Development, Evaluation & Engagement
  • Intermediate Business Case
  • Identify Proposed Project for Environmental Review

Phase 2

Project Selection


Phase 3

Project Delivery


  • Funding Strategy
  • Design
  • Construction
  • Testing & Commissioning
  • Ready for Service

Phase 0: Program Definition

This initial phase and effort set the Program foundation for Link21. Through early analysis and stakeholder and public engagement, BART and Capitol Corridor established the vision, Goals and Objectives, and Business Case, which is a decision-making framework that will be used to help identify and evaluate potential Link21 improvements. Work also included a Market Analysis, which was completed in 2021 and was the most detailed and comprehensive travel analysis ever performed for the 21-county Northern California Megaregion. Learn more about the engagement opportunities that occurred during Phase 0.

Phase 1: Project Identification

In early 2022, Link21 transitioned from Program Definition into the next phase of planning: Project Identification, marking a major milestone for Link21. During this current Program phase, Link21 is focused on developing and refining concepts based on regular input from key stakeholders, and the public as well as ongoing evaluation against established criteria as part of the Business Case. In early 2024, Link21 will identify if the new crossing will be a BART-gauge track or Regional Rail (standard-gauge track), each option offering key benefits and trade-offs. As the Program advances past this key crossing decision, options for new and improved station locations, and track alignment will be further defined to identify the proposed Project to advance into environmental review in late 2025.

Phase 2: Project Selection 
The Project Selection phase, tentatively scheduled to begin in late 2025 will establish an approved Project and associated implementation strategy for delivery through implementation of a required environmental review process.

Link21’s proposed Project, and any identified Project alternatives, are required by federal and state laws to have a full detailed environmental analysis performed to identify potential impacts and mitigations to minimize harms to environmental resources as a result of the future Project. These environmental processes are known as the National Environmental Policy Act (NEPA) and the California Environmental Quality Act (CEQA). 

Phase 3: Project Delivery 
The Project Delivery phase, tentatively scheduled to begin in 2039, will first focus on the final design of the approved Project, and associated funding strategy. Once completed and approved, a multi-year construction stage will begin followed by testing of the system and ultimately opening of service.  

All phases are dependent on available funding. BART and Capitol Corridor continue to identify funding sources, and work to secure the support and funding needed to bring the full Link21 vision to reality.