According to the transit agency, BART service on the Red Line was suspended Monday morning after an equipment problem occurred on the track.
BART issued an advisory about the problem shortly after 6:30 a.m.
Travelers going to Millbrae are advised to take the commuter train between SFO and Millbrae and transfer to or from the Yellow Line.
Millbrae riders from Richmond can take the Orange/Berryessa train and transfer to the Yellow/SFO train at MacArthur, transit officials said.
According to BART, a train was taken out of service due to an equipment issue, causing delays on the SFO line in the Antioch, Richmond, SFO and Millbrae directions.
At 8:43 a.m., BART announced that the problem had been resolved and normal service had resumed on the Red Line. However, the agency said major delays remained as the system recovered.