#CoolTrainTuesday is back!

The Heisler Locomotive Company built and streamlined this 0-8-0F for the 1939 World's Fair, making it the largest fireless steam locomotive ever built. "Fireless" means it was powered by steam from an external source, and what looks like a boiler is a pressure vessel. It remained in service at a power plant until 1969, well after mainline steam was gone from US rails. Now at the Railroad Museum of Pennsylvania.