Transbay Transit Center and Caltrain Downtown Extension

Transbay Transit Center construction photo

Transbay Transit Center and tower visualization

The Transbay Transit Center/Caltrain Downtown Extension (TTC/DTX) project will transform downtown San Francisco and regional transportation well into the 21st Century. The project consists of three interconnected elements: replacing the outmoded terminal with a modern terminal; extending Caltrain 1.3 miles from Fourth and King streets to the new TTC at First and Mission streets, with accommodations for future high-speed rail service; and creating a new transit-friendly neighborhood with 3,000 new homes (35 percent of which will be affordable) and mixed-use commercial development. The total program budget is currently estimated at $4.39 billion in year-of-expenditure dollars. In May 2010, the Transbay Joint Powers Authority (TJPA) Board adopted a $1.60 billion budget for Phase 1; on July 11, 2013, the TJPA Board approved a revised budget of $1.899 billion for Phase 1 of the project due to drastically changed market conditions, modifications necessitated by an earlier terrorism-related Risk and Vulnerability Assessment, and resetting contingencies and program reserve at prudent levels. (TTC, pedestrian ramps, and the train box, which is the underground portion of the TTC building that will house the Caltrain and high-speed rail station). The current estimate for Phase 2 (DTX) is $2.5 billion.

This is the largest project in the Prop K Expenditure Plan, which designates up to $270 million (in 2003 dollars) for this purpose. The Expenditure Plan specifies that the downtown rail extension and the terminal, known as the Transit Center Building, are to be built as a single integrated project. To date, the Authority has allocated $151.5 million in Prop K funds to the project, in addition to state Regional Improvement Program (RIP) funds.

TJPA has worked to offset the $310.4 million Phase 1 cost increase through value engineering, phasing, identification of funding and financing strategies, and reducing costs by re-bidding the steel superstructure. In 2013, the Transportation Authority approved programming of $41 million in additional Prop K funds to the project. These funds became available as a result of significantly reduced financing costs in the 2013 Strategic Plan baseline adopted by the Transportation Authority Board in July 2013. In June 2013, the Authority Board also programmed $6 million in OneBayArea Grant funds to bicycle and pedestrian elements of the project.

During fiscal year 2013-14, the designer has completed and submitted 100% documents of the main package, and issued for bids on April 1, 2014. TJPA expects to issue 40 trade packages during 2014. As of March 30, 2014, the Buttress, Shoring, and Excavation contract is reaching completion; excavation and micro-pile installation are complete and only 45 micro-piles remain to be tested. The Below Grade construction contractor continues work on geothermal system installation, waterproofing of the mud slab and walls, placing rebar for the mat slab, and placing concrete for the five-foot thick mat slab. Work is also in progress on and steel and concrete for the structural walls. The contractor for the steel superstructure has been working on pre-construction submittals and procurement of the steel and other long-lead items. Meanwhile, fabrication of the structural cast nodes is also under way.

On October 7, Tilly Chang, the Transportation Authority’s new Executive Director toured the construction site, together with Chair Avalos, Commissioner Mar, TJPA’s Executive Director Maria Ayerdi and staff member from both agencies.

On October 9, the TJPA executive team met with the Transportation Authority team to unveil TJPA’s proposal to pursue a Public Private Partnership for delivering the Downtown Extension (DTX). The Transportation Authority staff was receptive to the approach and offered its assistance and support for the development of the P3 option.

Downtown Extension (DTX)

The DTX is scheduled for completion in 2019; however, work is on hold due to a funding gap. Progress has been made in moving the project forward, as the Plan Bay Area Regional Transportation Plan/Sustainable Communities Strategy (RTP/SCS) Transportation Investment Strategy identified DTX as one of only two Bay Area priorities for $650 million in future federal New Starts transit funding. The regional endorsement of DTX positions the project well to receive federal funding the highly competitive national New Starts program. In 2014, Authority staff will continue to work closely with TJPA, the City and other funding partners to support delivery of Phase 1, to safeguard the project against any impacts of the expected dissolution of redevelopment agencies, and to advance strategies to close the funding gap for Phase 2.


Download the most recent Transbay Transit Center fact sheet.

Project Schedule

TIMEFRAMEspacer image
April 2009   Transit Center Final Design begins
August 2010   Operations begin at Temporary Terminal
August 2010   Demolition of old terminal begins
December 2010   Shoring Wall and Buttress construction begins
February 2013   Sub-surface construction begins
April 2014   Superstructure construction begins
April 2015   Exterior Enclosure construction begins
April 2015   Interior Finishes begin
October 2017   Bus Operations begin