BART recovering from major delays in Transbay Tube

Commuters are lined up to board a San Francisco train at the MacArthur BART station in Oakland, Calif. on Aug. 30, 2016. Commuters are lined up to board a San Francisco train at the MacArthur BART station in Oakland, Calif. on Aug. 30, 2016. Photo: Paul Chinn, The Chronicle Buy photo Photo: Paul Chinn, The Chronicle Image 1 of / 1 Caption Close BART recovering from major delays in Transbay Tube 1 / 1 Back to Gallery

BART says it is recovering from major delays caused by a debris fire in the Transbay Tube.

Agency officials said the fire beneath the tracks was extinguished by 7:40 p.m. Friday and that regular service was returning. BART initially reported the problem was caused by a “blown insulator.”

The burning debris prompted trains to be single-tracked across the bay for more than an hour, resulting in long backups in both directions. Residual delays were expected to continue for much of the evening.

“The good news here is the problem has been resolved,” said BART spokesman Chris Fillippi.

Kurtis Alexander is a San Francisco Chronicle staff writer. Email: kalexander@sfchronicle.com