An electrical problem caused major delays earlier today when it forced BART to switch the trains to manual mode, meaning they couldn't exceed 25 mph, spokesman Jim Allison said.
Service was hampered between about 1:25 p.m. and 2:15 p.m. as a result, and 20-minute delays were still being reported as of about 3 p.m.
Trains on the Fremont-Daly City and the Richmond-Daly City lines did not run through the Transbay Tube during the manual mode, Allison said.
The electrical problem occurred at the Montgomery Street station and involved equipment not operated by BART, Allison said.
The malfunction tripped BART's breakers and knocked the agency's electrical system offline, Allison said.
BART shares the Montgomery station with San Francisco Municipal Railway.