The Chicago & North Western was among the first railroads to acquire the "super-power" Berkshire type, receiving twelve locomotives from Alco's Brooks Works in Dunkirk, New York in 1927. They were similar in design to the Boston & Albany's A-1c class, weighing 397,00 pounds and exerting 67,200 pounds of tractive force (76,160 with booster). They had a 100-square-foot grate area, with 4777 square feet of evaporative heating surface and a superheater surface of 2243 square feet. Cylinder dimensions were 28x30 inches, with boiler pressure set at 240 p.s.i.
Having a driver diameter of 63 inches, comparable to those of most Mikado types, these early Berkshires could not develop the "super-power" potential for high-speed running; reportedly the C&NW used its 2-8-4s mostly for coal trains on its southern Illinois extension through Peoria. This undated image of No. 2809 that came to our collection from an eBay seller contains no information about photographer or location, but the identical image uploaded by Bud Laws appears in the Railfan.net ABPR Archive where it is located at the C&NW's Proviso Yard near Chicago and ascribed to William S. Kuba of Cedar Rapids, Iowa.