The service disruption began around 2:30 p.m. Saturday when a problem with the overhead wires tripped a circuit, knocking out power between the Castro and Embarcadero stations.
A train full of people had to be evacuated from an underground tunnel.
A bus bridge has been in place, but passengers say it just is not as fast as the light rail system.
Muni officials have not determined the cause of the outage and have not said when service will resume.
