New York Central No. 2256, shown here in a builder's portrait as "Big Four" (CCC&StL) No. 156, was a member of class H10a, delivered in 1922-23 by both Alco and Lima. Her builder's plate identifies her as an Alco product. The H10 class had 28x30-inch cylinders, 63-inch drivers, and a boiler pressure of 200 pounds per square inch. No. 2256 weighed 342,500 pounds and developed 63,470 pounds of tractive effort, with a booster adding 11,000 pounds. I had my first ride in a steam locomotive, at the age of eight or nine, in H10b No. 2345 at Jackson, Michigan, through the courtesy of an engineer friend of my father's.

The improved steaming capacity of the H10 led to the appearance of the "superpower" 2-8-4 type, the four-wheel trailing truck being needed to support an even larger firebox. The NYC's Boston & Albany subsidiary was the first to operate the new type, eventually having 55 Class A locomotives. The 2-8-4 took its name "Berkshire" from the New England mountains traversed by the B&A.