As the days of the steam engine were drawing to a close, many desperately looked for a modern solution to keep steam locomotives in operation. The diesel engine was pounding at the door, and it spelled the end for the fire-breathing, iron monsters of yesteryear. One idea was to create an engine that transmitted steam power to the wheels via a steam turbine. This had been tried in several different countries before the U.S., but amid World War II, while our nation looked for every opportunity to ship war materials from coast to coast, we dabbled in the turbine trade. In 1944, Baldwin Locomotive Works built the sole example of a turbine-class engine for the Pennsylvania Railroad. It was the largest direct-drive steam turbine locomotive in the world. Numbered S26200 on the PRR roster, the S2 had a maximum power output of 6,900 HP and was capable of speeds over 100 mph! Sounds like steam is making a comeback, folks!
However, the S2 had a fatal flaw; it was ineffective at low speeds. At high speeds, the S2 could propel heavy trains smoothly and efficiently. However, below about 40 mph, the turbine used enormous amounts of steam and fuel. The smooth turbine drive put far less stress on the track than a normal piston-driven locomotive. But poor efficiency at slow speeds doomed this locomotive, and with diesel–electrics being introduced, no more S2s were built. The locomotive was retired in 1949 and scrapped in May 1952.
Thus, the S2 turbine would fade from memory and be forgotten by all, right? Wrong!
