A person reported on the tracks near the BART Embarcadero Station Wednesday evening caused major delays in both directions, according to agency officials.
Trains were halted entirely for more than an hour, causing chaos for commuters until service resumed at around 6:20 p.m.
Travel through the Transbay Tube stopped completely around 5 p.m., according to BART. While Blue Line trains began running between Dublin and MacArthur stations within the hour, the Red and Green lines remained idle as of 6 p.m.
BART advised riders to choose alternate transportation to get to and from San Francisco and the East Bay and suggested using the Orange Line to travel within the East Bay.
The agency said East Bay riders who need to get to San Francisco could take the Orange Line to the 19th Street Station in Oakland and take the NL Transbay AC Transit bus across the Bay Bridge.
BART later posted a grainy image of the person suspected of walking onto the tracks and asked for the public's help identifying him.