Southern Pacific's Bayshore Roundhouse will soon be on the National Register of Historic Places. It is the only mainline roundhouse left in California. The other historic roundhouses in California are on the Sierra at Jamestown, the former State Belt in San Francisco, and at the Timber Heritage Association in Samoa.

http://ohp.parks.ca.gov/?page_id=24479

The Muni (SF Municipal Railway) Geneva carhouse is also listed at this same site.

Edit: I mean the office. The adjoining carhouse is gone.