John,
I don't know about a map of the tracks on the State Belt Line, but I will ask the reference librarian tomorrow when he comes back from his weekend.
For sure the NWP had car float operations to the Pier 43 slip until the 1920s. They had the UKIAH for standard gauge and the ferry Lagunitas for narrow gauge and passengers. Their last narrow gauge branch to Point Reyes went in 1930.
Down at the south end of the State Belt Line, the Western Pacific and the Sante Fe ran car floats into the China Basin slip, but they were standard gauge.
The South Pacific Coast only went to Alameda and by ferry to San Francisco. They went to standard gauge about 1907/8. Thet were delayed by the 1906 earthquake.
Ted Miles