Narrow Gauge bogies were common in Wisconsin for logging operations and Michigan for copper mines in the Keweenaw. Off the top of my head the Keweenaw Central Railroad and the Calumet and Hecla RR both operated NG bogies, the Keweenaw Central were 3ft and the C&H locomotives were 49in gauge because why not. The ones in Wisconsin were also 3ft. I have an image of an old Bogie loaded onto a SG flatcar to be shipped to a scrapper in one of my books somewhere. I think it is more likely that the 2 bogies we see here are from the Midwest.