No trains will be running between Union City and Hayward and Alameda-Contra Costa Transit District (AC Transit) buses will continue to shuttle riders between stations.
MORE: BART considers layoffs, station closures, reduced services to balance budget deficit
Crews have been working to repair fiber optic cables that were damaged by fire before service began Sunday morning, according to BART. BART says it was damaged by a fire that was not started by a BART crew.
The cause is under investigation.
ABC7 Eyewitness News contributed to this report.