BART reported major systemwide delays Wednesday morning after smoke was reported near the tracks by the Embarcadero Station but was back in service in less than an hour.
Spokeswoman Denise Gonzalez said service was restored by 9 a.m., though there was a "residual delay" of about 30 minutes from San Francisco.
Maintenance crews and San Francisco firefighters had given the all clear about 8:45 a.m. but had not figured out what had caused the smoke on the tracks about 8 a.m.
Gonzalez said there were earlier reports that indicated there was a fire on the tracks, but at this point, crews were still "investigating that."
