Berkshire locomotive
The Class A-1 Berkshire locomotive is a 2-8-4 steam locomotive first built in 1925 by the Lima Locomotive Works. The design was initially intended to improve on the company's USRA Mikado design (2-8-2), which was deemed to lack sufficient speed and horsepower. This was addressed by the inclusion of a larger, 100-square-foot (9.3 m2) firebox that required an extra trailing axle, giving the locomotive its distinctive 2-8-4 wheel arrangement.
The Berkshire locomotive was so named for its testing location on the Berkshire Hills of the Boston & Albany Railroad. After the Class A-1 successfully outperformed a Class H-10 Mikado, the Boston & Albany Railroad became the first to order the new Berkshires. Over 600 were built by the Lima Locomotive Works, the American Locomotive Company, and Baldwin Locomotive Works. A total of nineteen different railroads purchased Berkshires, including the Erie Railroad, who owned 105 Berkshires, more than any other railroad; the Chesapeake & Ohio Railway, who nicknamed theirs the Kanawhas; and the Louisville & Nashville Railroad's, whose locomotives were technically designated as Class M-1 but were referred to as "Big Emmas".
Today, three Berkshires, the Pere Marquette 1225 and the Nickel Plate 765 & 763, remain operational. The Pere Marquette locomotive served as the model for the steam train in the 2004 film The Polar Express. Other surviving non-operational Berkshire locomotives include four New York, Chicago and St. Louis locomotives, another Pere Marquette locomotive, twelve Chesapeake & Ohio Kanawhas and Nickel Plate 779 located in Lincoln Park, Lima, Ohio.