Just a guess on what was found in a search. I've heard of one off runs for customers or buyers/builders who dabbled with this kind of stuff over the years.
but.....
not a single mention of any Milwaukee
Maybe they're Standard gauge cars with homemade truck sideframes for conversion?
what's the cover of that book look like???
Brass G scale / gauge one locomotives including a Big Boy, Hiawatha, one of one GG-1, and more at Stout Auctions on August 17th | O Gauge Railroading On Line Forum (ogaugerr.com)
I think it would be great if MTH released a SD70ACE (SD70M-2) painted for NYSW. They announced it in the Dash 8 and never made it as far as I know.
70-2030-1 | MTH ELECTRIC TRAINS (mthtrains.com)