The BART Transbay Tube was shut down for about an hour late Tuesday due to a reported debris fire, according to BART.
At about 5 p.m., the San Francisco Fire Department asked BART to cut off power to the Transbay Tube after sparks were seen coming from the entrance of the Oakland side of the tube, BART said.
About 30 minutes later, BART said the eastbound tracks were reopened, and it began single tracking trains through the tube.
At about 5:55 p.m., both directions of the Transbay Tube were reopened, BART said, but the shutdown caused major delays systemwide.