This locomotive was a unique prototype built for the growing freight demands after the Great Patriotic War, utilizing the Brown engine with opposing pistons. It had the wheel arrangement 2-10-4 and the cylinders were mounted above the third driving axle. This resulted in smaller moving masses, intended to reduce the hammer blow on the tracks. Maximum power was produced with an axle load of 23 tonnes, made possible by new tracks. Its indicated continuous power is being given with 2,500 hp, but it is likely that the large boiler was able to produce more power. Nevertheless, this locomotive was only tested for a short time and diesel locomotives were ordered instead. The later whereabouts of the ОР23 ware uncertain, but it was probably passed back to the manufacturer and scrapped.