In 1961, SP had for sale at Sacramento, CA three section cars. Two were small and one was a larger section gang car. Price was $50 each. One was sold to Portland Zoo in Oregon and regauged to 30 inch. The other small on was sold to a local individual and resold in the late 1960's. The large one was sold to my friend in Roseville. CA. In the late 1960's he sold it to an individual in Folsom, CA. It then disappeared and I was unable to located the individual. The one my friend bought looked identical to the one in your photos. There is a good possibility if you live here in California, it could be the same car my friend owned.