All subway trains were shut down this evening because of an electrical signaling problem from a blown transformer, Muni spokesman Paul Rose said.
The transformer blew around the Van Ness station at about 5:45 p.m. leading to the service outage, Muni spokesman Paul Rose said.
He said Muni crews are working with PG&E to restore service as quickly as possible.
The transformer was part of Muni's infrastructure, Rose said. PG&E responded and checked their equipment but did not find a problem, but assisted Muni in making repairs, PG&E spokeswoman Jana Morris said.
Bus shuttles are available for stranded Muni passengers between the Embarcadero and West Portal stations tonight. Rose recommended travelers check Twitter for updates.
The outage is unrelated to an earlier incident where a wheelchair-bound woman was hit by an F-train near the corner of Church and Market streets.
That woman was transported to San Francisco General Hospital with life-threatening injuries, according to police.