The Rotating Machinery Corporation, like ILW Truck, is a spin-off from the PV&T’s Portland Shops that builds traction motors for both the shops & some of ILW’s higher-horsepower units. It is a subsidiary of ILW instead of the PV&T because the PV&T is not in the business of building motors for railways outside the United Railways Trust.
When the PV&T started building their own trucks (after their long-time suppliers got out of the casting business) and started supplying designs to ILW, the Parsons Vale Trust decided to spin that department off into an ILW subsidiary. Soon after that, the Parsons Vale shops started building their own high-horsepower traction motors because none of the other traction motor manufacturers supplied motors that had the combination of power & overload capacity that were needed for the higher-horsepower motors that the shops were building. And then ILW asked for designs that would work with their high-horsepower diesels, and before you knew it this department, too, had been spun off into a new ILW subsidiary.
It operated out of the Portland Shops for 5 years after that, while a new assembly plant was built at the Sanford, ME airport (on the Atlantic Shore Line, which already had a little-used spur to the airport industrial park.)
It supplies motors to the Portland Shops, ILW, and has built some fairly huge traction motors and generators for freighters & warships.