BART Link21 Program

Multi-project program is designed to better-connect Northern California’s 21-county region

Link21 aims to improve connections between BART and the Regional Rail train system in Northern California, streamlining travel for everyone living and working in the 21-county Northern California megaregion. A key element of Link21 is the construction of a second underground train crossing, which would enhance service reliability and access to destinations in the greater San Francisco Bay Area, the Sacramento area, the Monterey Bay area, and the Northern San Joaquin Valley.

In 2021, the California State Transportation Agency estimated that Link21 will boost the megaregion’s economy by $145 billion and generate 377,000 new jobs. Initially, the consultant design team will identify alignments and station locations and evaluate their effectiveness in terms of operations, service, constructability, and impact on communities. The architects will focus on station location, layouts, and the potential for companion projects to improve the quality of life and environments in each area.

Related neighborhood-enhancing transit projects: Hallidie Plaza Revisioning, 24th & Mission Plaza Modernization, West Oakland Station TOD, Glen Park Better Neighborhoods Master Plan


21-county region including Sacramento, San Francisco Bay, Northern San Joaquin Valley and Monterey Bay


BART and Capitol Corridor with support from California State Transportation Agency

Prime Consultant

Arup Engineers & WSP joint venture

Lead Architect

Robin Chiang & Company

Project Duration

2022 – ongoing