An evacuation due to a smoke alarm at the SFMTA's cable car barn, and a subsequent power outage, led to a suspension of service on all cable car lines Thursday afternoon.

Notice of the service shutdown came via Twitter at 1:45 p.m., and initially the reason why the cable car barn was evacuated was not disclosed.

The SFMTA later explained to KPIX that a smoke alarm had gone off, but that turned out to be a false alarm. It's not clear if this was connected to the power outage, but the outage was ongoing after the smoke alarm issue was cleared.

Bus shuttles were dispatched to provide service to cover the Powell, Powell-Hyde, Powell-Mason, and California Street cable car lines.

It's not clear when the cable cars will come back online.

Photo: Daniel Abadia