キー・システム
Streetcar service across the East Bay was historically provided by the Key System, incorporated in 1902 as the San Francisco, Oakland, and San Jose Railway. An amalgamation of several streetcar companies established in the late part of the century, the Key System provided interurban routes across Alameda county, with connections to San Francisco ferries via their private Key System Pier. Southern Pacific ran a competing system, East Bay Electric Lines, until they, too, had the Key System take over operations. When the San Francisco–Oakland Bay Bridge opened in 1936, Key System cars could make the trip directly to the Transbay Terminal across the lower deck. Streetcars were replaced with busses in 1948 and transbay service halted in 1958. The system's assets were sold to the newly formed AC Transit in 1960.