SAN FRANCISCO --Outbound San Francisco Municipal Railway trains were delayed this morning due to a severed signal cable between the Civic Center and Montgomery stations. Signal cables allow communication between trains and control signals throughout the subway. Outbound trains between the Embarcadero and West Portal stations had to switch over to manual mode, Muni spokesman Paul Rose said. "Each individual operator is having to individually sustain communication with central control," Rose said this morning. Limited outbound underground service continued, but Muni set up shuttle buses to mitigate station congestion. Rose said Muni sent out crews to identify the problem, which was reported at about 6 a.m. By 12:20 p.m., the damaged cable was fixed and normal outbound Muni service had resumed. Inbound service was not affected, he said.