San Francisco’s answer to Grand Central Station in New York—Pelli Clarke Pelli’s under-construction Transbay Transit Center—is experiencing $300 million in cost overruns, which will require alternative funding to complete its signature feature, a rooftop park over its five-story terminal. The $1.9 billion project is expected to carry 100,000 riders daily.

Currently funded by a mix of local, regional, state, and federal monies, the project is set to connect San Francisco’s fragmented public transportation. This will include the transit center, the 61-story Salesforce Tower, a bus terminal, and light rail extensions from Mission and First streets. A local district plan will bring affordable and market-rate housing, over 11 acres of new parks, restaurants, shops, and other amenities to the area. The transit center will also support California High Speed Rail.

Local San Francisco firm Peter Walker and Partners has designed the 5.4 acre rooftop park, which features an amphitheater, gardens, and a children’s playground, and sustainable elements like stormwater management. A funicular will bring visitors up from the street and bridges will connect the park to neighboring buildings.

Despite reports that the park will be cut—the San Francisco Chronicle recently stated the city would need to raise $24 million from private donors and nonprofits to add the plants, trees, and other design elements beyond the walls and drainage—developer Transbay Joint Powers Authority (TJPA) recently issued a statement that says otherwise.

Adam Alberti, spokesman for the TJPA maintains that the park will open as part of phase one in late 2017, concurrently with the new transit center: “The TJPA and the Mayor’s office agreed to work together to ensure that the roof top park opens concurrently with the opening of the Transit Center.”

Funding could come from a special tax area around the Transbay Transit Center, called the Mello Roos Community Facilities District. Neighboring property owners would build taller buildings in exchange for paying higher taxes. While this model was originally created to help fund the light rail extension in phase two, it could help support the rooftop park and transit center construction in phase one. Another option is corporate sponsorship.

Several design elements have already been altered, most notably the transit center skin, which will be constructed from perforated aluminum instead of glass.