| Unique to the Union Pacific was the 4-12-2 wheel configuration built by Alco in the 1920's. Eventually 88 of these unique and massive monsters were built. Specs - serial #66544, class UP-1, 67" drivers, 220 psi boiler pressure, three 27" diameter cylinders (two with 32" stroke and one with a 31' stroke), engine weight of 496,000 lb, tractive effort of 96,646 lb. Retired in May of 1956. Eventually preserved at the LA County Fairgrounds, Pomona, CA. The photo is from the collection of Howard W. Ameling. |