The Schienenzeppelin, or rail Zeppelin, seems like exactly the kind of preposterous contraption only a steampunk artist could imagine — a pusher-prop-driven locomotive — but it really ran:
Conceived and built in 1930 by the German rail company Deutsche Reichsbahn, the Schienenzeppelin was a design alternative to the streamlined steam locomotives of its day. It was a slick and relatively lightweight at 20 tons, running on but two axles and powered by a 46-liter BMW V-12.
The same engine was later used to power the light bombers of the Luftwaffe. The engine sent 600 horsepower to a massive ash propeller, tilted seven degrees to produce downforce. [...] Originally good for 120 mph — on par with the fastest streamlined steam locomotives — the Schienenzeppelin topped out at a magnificent 140 mph in the summer of 1931. It was a record that stood for 23 years and was never surpassed by a gasoline-powered locomotive.
Unfortunately, the train never made it into production. Problems with propeller safety and reliability kept it from attaining mass production. The prototype that set the speed record was dismantled in 1939 on the eve of World War II.