My fuzzy memory recalls the platform shelter at the end of the line station. Right next to that was a very small enclosed place with a counter and maybe 6 to 8 stools. My big treat there was a scoop of chocolate ice cream with chocolate syrup on top. And a cup of water.
And why should a child remember the water? Must have been pretty special. It was served ice cold in a paper cone shaped cup that fit into a black resin(?) container and was the best water I ever tasted. Have read that there was a well known spring that ran under that area and down into the bay. It was supposedly tapped and piped to part of the Presidio for some time, but eventually was replaced by something more "modern".
That may be the spring/well that legend has it was good luck for expectant mothers.
(Sorry - let's get back to streetcars, etc.)