A rough week for BART continued early Friday, when the transit service lost its ability to send trains through the Berkeley Hills tunnel.
A ventilation problem inside the tunnel caused by a mechanical issue forced the closure of the yellow line through the tunnel in both directions, BART spokeswoman Anna Duckworth said. The yellow line runs from Antioch to the San Francisco Airport.
County Connection buses in Contra Costa County were summoned to provide a bridge for commuters between the stations, but BART advised riders to seek other forms of transportation.
BART restored service by 7 a.m., and trains were running through the tunnel, but residual delays were continuing, Duckworth said.
Earlier this week, BART was hit with two major delays during its morning commute. Several vegetation fires near track lines stopped service between the Concord and Pleasant Hill stations Tuesday, the same day an equipment problem caused delays of more than 20 minutes on the Berryessa line.
A man walking on the tracks also caused a major delay on the Berryessa line on July 12. That same day, a train on the Antioch line broke down inside the Berkeley Hills tunnel.
A person on the tracks also caused major delays on the San Francisco line July 11.
