I believe the station was called Eureka Valley after the name of the neighborhood and was supposed to serve the general area as the post-Earthquake plan was for the streetcars to continue underground below Market St.
Two of the shelters above the staircases are gone without a trace, but Frank is right about the oddly wide sidewalks on Market at Eureka(?)with the steel plates being the site of the stairs to the station.
When it was operational it was rarely used. I guess it was easier to get a streetcar at Castro and Market than negotiate what was probably the equivalent of two stories of stairs