Built starting in the 1940s, the six-wheel Commonwealth freight truck was designed for heavyweight freight cars (although mainly used under 110-130 ton Commonwealth cast-steel depressed-center flats). The Commonwealth is similar in design to the Buckeye six-wheel freight truck, just (for whatever reason) not quite as popular. These Commonwealth heavy duty trucks can still be found on the rails today (of course, as pictured above, they have long since been converted to roller bearings).
Micro-Trains makes the only Commonwealth freight truck in N scale (modeled after the original friction bearing version) -
