The Silicon Valley BART extension is an ongoing effort to expand service by Bay Area Rapid Transit (BART) into Santa Clara County via the East Bay from its former terminus at the Fremont station in Alameda County. Planned since at least 1981, the project has seven stations in three sequential phases. The first phase was the Warm Springs BART extension, built by BART at a cost of $790 million, terminating at the new Warm Springs/South Fremont station. Construction began in 2009, and the extension and new station opened in 2017.