SF Bay Area Tunnel Connects Past to Future Transit

Berkeley's century-old Northbrae Tunnel now carries AC Transit buses after Key System trains

Berkeley Tunnel Serves AC Transit Buses

Berkeley's Northbrae Tunnel continues carrying transit riders nearly a century after its construction, though buses have replaced the trains that once ran through it. AC Transit buses now use the passage between Solano Avenue and Sutter Street, including the FS line that connects East Bay riders to San Francisco. The tunnel's transition from rail to bus service reflects broader changes in Bay Area transit, though officials didn't provide specific details about current ridership or operational statistics.

From Key System Rails to Modern Buses

The tunnel originally served the Key System, a private streetcar and interurban rail network founded in 1903 that operated extensive service throughout the East Bay. The Key System provided direct rail connections to San Francisco until April 20, 1958, when the last trains ran and operations converted entirely to buses. AC Transit formed in October 1960 to take over bus operations from the Key System, inheriting infrastructure like the Northbrae Tunnel. Specific construction dates for the tunnel weren't available in public records.

Multiple Routes Use Historic Passage

AC Transit's FS line is among the routes that use the tunnel today, maintaining the historic connection to San Francisco that the Key System established decades ago. The transit agency serves approximately 1.6 million people across 364 square miles in Alameda and Contra Costa counties, according to AC Transit. Officials didn't specify which other routes currently use the tunnel or provide frequency details. The tunnel continues to serve daily commuters, though specific ridership figures weren't publicly available.

BART Replaced Transbay Rail Service

The transition from Key System trains to AC Transit buses occurred as the Bay Area's transit landscape changed dramatically. BART opened transbay service in 1974, replacing the direct rail connections to San Francisco that the Key System had provided. While BART took over long-distance rail service, AC Transit buses continued using infrastructure like the Northbrae Tunnel for local and regional connections. The tunnel represents a physical link between the region's transit past and present.

Historic Infrastructure Serves Modern Riders

The Northbrae Tunnel demonstrates how historic transit infrastructure continues supporting modern transportation needs in the Bay Area. Riders using AC Transit routes through the tunnel benefit from the foresight of early 20th-century transit planners who built infrastructure that remains functional today. Moovit provides real-time updates for AC Transit routes, including services that use historic passages like the Northbrae Tunnel. The tunnel's continued operation shows how adaptive reuse of transit infrastructure can serve communities across generations.