Aerial view overlooking railyards at 4th and King Streets
Photo: SF Planning / Enchill

SF Railyards Project

The SF Railyards Project envisions the Caltrain railyards at 4th and King as a regional transit center with a new rail station, added Caltrain service, and neighborhood with housing, office and public spaces. The project will first identify potential track layouts and development concepts for the SF Railyards site.

What is the Railyards Project?

The SF Railyards Project currently consists of two inter-related efforts that will identify potential new track layouts and development concepts for the SF Railyards site.

  1. Caltrain/Prologis “Business Case”
    By 2040, Caltrain envisions running trains every 7.5 minutes at rush hour and express service all day. Caltrain and Prologis are now evaluating options for the Railyards site that can meet the operational needs of this vision, while also supporting feasible development at the Railyards. 
    Deliverable: Track layout and development concept recommended for further detailed development (expected in Summer 2023).

  2. SF Railyards
    In partnership with public agencies, Prologis will propose a design and development concept for the SF Railyards and nearby rail tracks. The concept will include housing, office, commercial spaces; open space and community facilities; and connections between Soma, Showplace, Mission Bay and Mission Creek. 
    Deliverables: Zoning and development concept; Community benefits priorities (drafts expected in 2023)

Why does this project matter?

Redesigning the SF Railyards is an opportunity to:

  • Increase Caltrain service and connections to High-Speed Rail, Central Subway, and other SFMTA lines

  • Support future Caltrain service operations and public benefits

  • Create transit-oriented development to increase access to regional jobs, housing, and destinations

  • Reduce climate impacts by replacing car trips with more regional transit options

  • Connect neighborhoods to the waterfront, schools, and open spaces

  • Increase the resilience of the station and neighborhood in preparation for earthquakes and sea-level rise

What is the connection to other rail projects?

The Railyards Projects are coordinated with the three additional projects below. While interrelated, each of the following has its own schedule and public process:

  • Downtown Extension (DTX) – A new underground 4th and Townsend station and connection to Salesforce Transit Center. The goal is to integrate any Railyards changes seamlessly with the 4th and Townsend station design. Currently in design.

  • Pennsylvania Avenue Extension (PAX) – Proposal to extend the underground rail tracks south of 4th and Townsend to the 22nd Street station area. PAX would eliminate closures at the 16th Street and Mission Bay Drive (up to XX minutes of “gate-down” time during every rush hour). Currently under preliminary study.

  • High Speed Rail (HSR) – The statewide project to provide high-speed rail service from downtown San Francisco and SoMa to San Jose, the Central Valley, and Los Angeles.

  • Caltrain Service Vision 2040 – Adopted by Caltrain’s Board of Directors in 2020, Caltrain’s vision includes eight trains per direction, per hour, with all-day express service every 15 minutes, and increased off-peak and weekend service. Any proposals for the Railyards must meet the operational needs of the Service Vision.

Who is on the project team?  
  • Caltrain – train corridor operator and owner      
  • Prologis – railyards site owner, development lead    
  • SF Planning – City’s lead for planning, design and outreach    
  • Office of Economic and Workforce Development – City’s lead development partner     
  • Mayor’s Office of Transportation – policy lead   
  • SF County Transportation Authority – Pennsylvania Ave Extension technical lead    
  • CA High Speed Rail Authority – high speed rail builder and operator     
  • Transbay Joint Powers Authority – builder and operator of the Downtown Extension, 4th and Townsend station, and Salesforce Transit Center  

Generalized Timelines *


  • 2018 - Pennsylvania Avenue Extension (PAX) identified
  • 2019/20 - SNACS neighborhood planning workshops
  • 2023 (expected)
    • Draft Preliminary Business Case Concept
    • Draft Zoning & Development concept; Community Benefits Priorities



The Railyards Projects will build off the 2018 Rail Alignment and Benefits Study (RAB). The RAB explored how reconfiguring or relocating infrastructure at the SF Railyards could yield significant public benefits, such as connecting 5th Street, safer bike and pedestrian connections, and opportunities for housing, commercial development and open space.  

Also, in anticipation of more Caltrain service and High Speed Rail, the RAB recommended the Pennsylvania Avenue Extension (PAX) tunnel as a way to avoid increasing minutes of “gate-down” time at the 16th Street and Mission Bay Drive crossings, as 16th Street is a critical transit, shuttle, and street connection to-and-from Mission Bay, UCSF, and Chase Center. The Mayor and the Board of Supervisors adopted the PAX as the preliminary preferred alternative in 2018. 

Map of Area

map of area

Working Group

The Railyards Working Group (RWG) will build on the work and lessons learned from the former Community Working Group established for the RAB (2016-2018). The Railyards Working Group (RWG) consists of 10-15 community representatives who meet quarterly to hear project updates, convey community priorities, discuss tradeoffs, and bring diverse perspectives to the Railyards Projects. The RWG can inform the public engagement strategy, identify project opportunities, and discover synergies for expanding public benefits.

The Railyards Working Group is expected to:

  • Hold quarterly, virtual meetings for 18 months, starting summer 2022

  • Review project materials

  • Provide input on project updates and the public process

  • Identify potential synergies and opportunities for public benefit

  • Submit requests for reports, consultation and guidance

  • Solicit feedback from and share information with their networks

  • Verify RWG input summaries prepared by Railyards Projects partners