Locomotive

Would say you are correct as I know Back to the Future was filmed near Jamestown in California. Railtown is a train museum in Jamestown where a lot of filming took place (Pettycoat Junction was one) if I saw the same episode you reference I also noticed that the scenes depicting the Wells Fargo auction are filmed in Columbia a restored gold mining town near Jamestown. My family has a cabin not far from either and would visit both at least once each summer growing up.