BART was experiencing a major delay system wide Monday morning due to an equipment problem on the track in the Transbay Tube, officials said.
As of 7:55 a.m. there was no Red or Green line service as trains were using one track to get through the tube.
The Red Line runs between Richmond and Millbrae and the Green Line from Daly city to Berryessa/North San Jose.
The problem was first reported about 6:09 a.m. Monday.
BART was advising riders of transfer alternatives.
BART has not yet said when regular service might resume.
Check back for updates on this developing story.