San Francisco’s ‘Grand Central Station’ Project Faces Funding Uncertainty

A vital rail infrastructure project in San Francisco, envisioned as a West Coast equivalent of Grand Central Station, is facing potential delays due to uncertainty over crucial state funding. The Metropolitan Transportation Commission has previously endorsed granting $750 million from the state’s “cap and invest” funds towards the completion of the Portal, a rail tunnel designed to bring both Caltrain and future high-speed rail services into the underground level of the Transbay Transit Center. However, this funding is now reportedly at risk as the California Air Resources Board (CARB) is said to be “re-negotiating” state allocations.

The Portal project aims to connect the Transbay Transit Center, also known as the Salesforce Transit Center, with Caltrain’s existing terminus at Fourth and Townsend streets via a 1.5-mile tunnel. This connection is central to creating a unified regional and intercity rail hub in downtown San Francisco.

When Operational, Projected Benefits

Adam Van de Water, Executive Director of the Transbay Joint Powers Authority (TJPA), highlighted the project’s significance for carbon reduction, stating it is “the most cost-effective program for carbon reductions, coming in only after BART’s core capacity program.” He noted that the $750 million represents “10 percent of the construction costs.”

The TJPA anticipates that if the funding is secured and the project progresses as planned, trains could begin running into the Transbay Transit Center’s basement by 2035. The projected impacts of the operational tunnel are substantial: an annual reduction of over 76 million private car miles and a decrease in greenhouse gas emissions exceeding 30,000 metric tons. Commuters are expected to save between 30 to 45 minutes on their daily regional journeys.

Progress and Potential Setbacks

Van de Water discussed the CARB funding issue during a recent tour of the “train box” – the 160,000-square-foot space beneath the Transbay Terminal designed to accommodate trains, platforms, and a mezzanine level. This underground area was completed in 2018, along with the bus platforms and the elevated park on the roof. However, the train box has remained empty, awaiting the completion of the connecting tunnel.

The train box is designed with “break out” panels on its eastern end to connect to the Portal tunnel. It also features panels on the west side, intended for eventual integration with a planned second Transbay tunnel under the Link 21 program, which would enable through-running services. However, the Link 21 program is described as a more distant and uncertain prospect.

The total estimated cost to complete the Caltrain and high-speed rail connection is $7.5 billion, with over two-thirds of this amount already accounted for. The TJPA is concerned that the ongoing re-evaluation of CARB funds could jeopardize the project’s financial stability. “Every time funding gets unwound and has to be re-addressed, time is wasted and costs rise,” Van de Water stated.

Negotiation Efforts

In response to the potential funding challenge, Van de Water indicated that TJPA staff plan to travel to Sacramento to negotiate with CARB for the preservation of these funds. Despite the current uncertainty, he expressed confidence in the eventual completion of the rail connection, stating, “It’s when, not if,” referring to trains arriving at the transit center.

Key facts
| Project Component | Description | Status |
|—|—|—|
| The Portal | Rail tunnel connecting Caltrain and HSR to Transbay Transit Center | Funding potentially at risk |
| Transbay Transit Center Train Box | Underground rail station space | Completed in 2018 |
| Projected Operational Date | 2035 (if funding secured) | Target |
| Estimated Total Cost | $7.5 billion | Partially funded |

This development signifies a critical juncture for San Francisco’s urban rail infrastructure. The successful completion of the Portal tunnel is essential for realizing the full potential of the Transbay Transit Center as a major multi-modal transportation hub. Beyond improving regional commute times and reducing private vehicle use, it is a key component in the long-term vision for high-speed rail integration on the West Coast. The outcome of the funding negotiations with CARB will significantly influence the timeline and certainty of these urban and regional transport goals.

Source: https://sf.streetsblog.org/2026/06/04/dream-of-a-grand-central-station-for-the-west-at-risk-of-further-delay

Key facts