That big county park out at Point Pinole used to be a huge powderworks with its own railroad. Below are two details from the Richmond and Mare Island 7.5 minute USGS quads showing the whole area. There were two rail connections to the SP, a siding at Sobrante, the station at the north entrance to the park, and another at Giant, which was south of of the southern entrance to the park.

I was researching the railroad there and didn't really find anything helpful. The big question I have is whether the railroad was standard gauged in its entirety or only in part?

Interesting history. It shurt down in early 60's. Bethlehem Steel bought the property, thinking they were going to build a huge plant there. Unfortunately that never happened, and now it is a county park, which I guess is a fine alternative by any measure.

Thanks if any of you are experts on this area and know about this fascinating but hidden part of Bay Area railroad history.

Here are the topo details I mentioned above: