HO Scale - GP38-2 - Southern Pacific #170 - with DCC & SoundDescription: By the early 1970s, many first generation diesels were reaching the end of their service lives. The most common replacement locomotive became the GP38 2. EMD began production of the 16 cylinder, non turbocharged, 2000 horsepower engine in 1972. Unlike the GP38's engine, which drove a generator to supply power to the traction motors, the GP38 2s prime mover drove an alternator which produced AC electrical current that was rectified to DC