For much of the twentieth century, the Union Pacific had a love affair with massive, bigger-than-life locomotives. Some examples, like the Challenger and Big Boy, were great successes, while others like the gas turbines and DD40AX "Centennial" diesel were noble failures. One of the UP's earliest and most successful big engines was the 9000-class 4-12-2, which boasted the longest rigid wheelbase of any American steam locomotive. Designed for fast freight service, the eighty-eight 9000-class engines were built by Alco in 1926-30, during a period when low-speed "drag" freight service - the norm on American railroads for decades - was being largely supplanted by freight trains running at passenger speeds. The 9000s could haul a mile-long train at 50 mph, twice the speed of the Mallet articulateds they replaced.
Known as a "Union Pacific" type for their wheel arrangement unique to the U.P., the 9000s were also the most successful three-cylinder rod locomotives ever built. The third cylinder was placed between the two outside cylinders and drove a rod connected to the second axle, which was shaped like a crankshaft rather than a straight axle. A pair of hinged rods driven off the outer cylinders, and clearly visible on the pilot in front of the cylinders, operated the third cylinder's valve gear. The rest of the middle cylinder's machinery, however, was not so visible or accessible, and tended to receive less than the optimal amount of attention from shop crews. Despite the maintenance headaches of the third cylinder, however, the 4-12-2s proved versatile and dependable. When faster and more powerful Challengers and Big Boys replaced them as the UP's premier freight engine, the 9000s became the principal freight power on the Nebraska division, where they served until early 1956. Engine No. 9000 was saved from the scrapper and resides today at the Los Angeles County Fairplex in Pomona, CA.
Returning for the first time since 2007, the 9000-class joins the other unique and massive UP power that has graced the Premier lineup. With smoother operation than any other model of this unique engine, our 4-12-2 will feature the wealth of added-on details you expect in a Premier locomotive - including operating third-cylinder valve gear on the pilot - and a correct six chuffs per driver revolution.
