The Caltrain Downtown Extension is part of the San Francisco Transbay Terminal Project.
The plan is to extend Caltrain 1.3 miles through an underground tunnel in San Francisco, to a rebuilt Transbay Terminal near 1st and Mission Streets in the heart of the financial district. The Terminal would connect Caltrain, AC Transit, Golden Gate Transit, and SF Muni, with Caltrain in the basement.
While the downtown extension benefits Caltrain and future California high-speed rail, they are not the lead agencies for the project. Responsibility for managing, planning, and building the Caltrain downtown extension belongs to the Transbay Joint Powers Authority.
Getting the downtown extension built was one of our organization’s primary goals in the early 1980’s. This project has survived near-death on several occasions, pulling through because of the hard work and personal sacrifices of advocates to keep it alive against severe obstacles. We owe a previous and current generation of activists a debt of gratitude for the progress that this project is made.
The Transbay Transit Center (bus terminal and train box) is under construction. The tunnel from 4th & King to Transbay has received environmental clearance but has yet to be funded. The City of San Francisco has proposed to apply for federal “New Starts” fund for the Caltrain/HSR extension after the Central Subway project, which the city has earlier applied “New Starts” for.
Please see our Transbay Terminal page for more information.
San Francisco is considering ideas to potentially realign the Caltrain tracks in the Mission Bay area to make room for development on the 4th & King site. A plan to realign the tracks could significantly delay the project with additional environmental studies as well as increased project costs. BayRail Alliance urges San Francisco to keep its commitment toward DTX as currently planned.
Green Caltrain updates on DTX
- SF downtown extension: 1 year and $1 billion to knit city together
- San Francisco Downtown Extension – Pennsylvania alignment recommended, more information late May
- Study results reveal planned – is the Downtown Extension logjam about to break?
- News about Downtown Extension options delayed following Mayor Lee’s death
- Will San Francisco keep moving on the downtown extension?
- Cost estimates up for downtown extension, ticket surcharge proposed to close funding gap
- High Speed Rail to Bay Area first – how will this affect the Caltrain corridor?
- San Francisco to reveal first results of study to build on Caltrain railyard, boulevardize I280
Streetsblog articles on DTX
- Eyes Under the Street: A Tour of the Transbay Train Box
- Advocates, Angered by Townsend Project Cancellation, Dominate SFMTA Board Meeting
- SFMTA Cancels Townsend Safety Project; Advocates Fight Back
- Another Bad Crash as Embarcadero Safety Project Languishes
- Today’s Headlines
- City Staff Aligns Behind a Pennsylvania Ave. Tunnel for Downtown Connector
- This Week: DTX, Women’s Bike Maintenance, City Trivia
- Today’s Headlines