A 10-inch section of broken rail wreaked havoc on BART this morning, causing delays that may well continue into the evening, SFGate reports. The track deformity is located somewhere between the Civic Center and 16th Street stations, prompting trains to be single-tracked through San Francisco and severely limiting East Bay bound service.

Repairs are expected to take four to six hours and delays will likely persist into the evening commute. MUNI is offering mutual aid as an alternative, and AC transit was accepting BART tickets. ABC7 reported major traffic delays on freeways as well, making transit by car an unappealing alternative.

According to SFGate, San Francisco Airport bound trains are the only ones running past Montgomery station, with all other lines offloading passengers at earlier stops: Fremont/Daly City trains are stopping at MacArthur station, and Dublin/Daly City lines are turning around at Montgomery station.

UPDATE: As of 4:11 p.m. BART was reporting that repairs had been completed and that tracks through San Francisco had reopened. Delays in the system are persisting, however, due to a major power outage between Castro Valley and Bay Fair. Power has been restored and service is resuming, but it may take time for the system to return to normal.