Penn Machine Company - OEM and aftermarket gears and components for transit, railroad, mining, steel and construction industries Penn Machine manufactures OEM and aftermarket wheels, wheelsets, trucks, axles, gears, and gearboxes for transit, railroad, and industrial. Penn Machine began business as a coal company and pioneered the manufacture of quality replacement parts for coal mining equipment. Over the years, PMC has grown to become a major supplier of heavy-duty OEM and aftermarket components for the transit, railroad, mining, steel, construction, and general industries.