There were four Municipal Railway Street Car lines on Geary:
A GEARY AND TENTH was the original Geary Street line beginning service as the Muni's first line on December 28, 1912. It ran over Geary to Tenth going down Tenth to Fulton where John McLaren forbad entry into Golden Gate Park. It ran until the early 1930s when competetion from the last new Market Street Railway line, the 31 Balboa caused its demise.
B GEARY AND OCEAN began service to Thirty-third a few months after the A line began. It soon extended to Playland over pretty much the current 38 GEARY OCEAN BEACH branch except in those days Geary was a two-way stree over its entire run.
C GEARY AND CALIFORNIA and later C GEARY AND SECOND shared its route with the B line to Second Avenue to Cornwall and California to Thirty-Second then Thirty-Second to a private right of way around what's now the Coastal Trail to the shed near present day Louie's. The Lands End portion washed out permanently in 1925 and the line was cut off at Thirty-Second. In the years after the 1944 merger of the Municipal Railway and the Market Street Railway the line was cut back to Second and Cornwall. Street car service on the B and C ended in December, 1956.
D GEARY AND VAN NESS ran out Geary to Van Ness then merged with the H POTRERO to Union, then out Union through Cow Hollow to its terminal shared with the E UNION within the walls of the Presidio.
For a history of all the Muni lines and its various predecessors, check out INSIDE MUNI, Fred Stint's book, or Charlie Smallwood's WHITE FRONT CARS.