Diesel Over Steam

     We all know that modern, efficient diesel-electric drive systems replaced steam as the prime mover of locomotives, but did you ever wonder why?  A large steam engine is fairly light and simple for a given horsepower, especially compared to a diesel, and that goes much more so for early diesels.  

     It turns out Fleet Admiral Chester W. Nimitz, the WW II Commander in Chief, Pacific Ocean Areas, is one reason.  In 1908, while an ensign and in command, he managed to run a destroyer into a mud bank (or possibly a sand bar, accounts vary) and was court-martialed, given a letter of reprimand and, perhaps not coincidentally, shunted off to the submarine service.

     U. S. Navy submarines burned gasoline at the time and it was about as bad as you might expect: volatile fuel vapors, occasional exhaust leaks, and every problem you might imagine from a brass-lamp-era automobile, only underwater and on a larger scale.  In 1913, after having worked his way up though the command of successively larger and more complex submarines and then command of the entire Atlantic Submarine Flotilla, Nimitz spent the summer in Germany, studying diesel engines.  He liked what he saw and the U. S. Navy began to go diesel, beneath and above the waves.

     Nimitz managed to get his career back on top of the water and continued to rise; meanwhile, in 1932, "U. S. Navy opened a competition for the development of a light-weight diesel engine, more suitable to submarines than any currently in production. While the number of engines which might be purchased for submarines was too small to justify the investment, there was a large commercial market waiting in the wings: the railroad." (Italics mine.  Found at World Submarine History Timeline and bring your lunch, you'll be awhile.)

     A World War slowed changes to civilian infrastructure but afterwards, the big diesel locomotives came roaring in.  If Ensign Nimitz hadn't found a mud bank to get stuck on, barely before the first Model T had rolled off the assembly line, it might have taken even longer.