Louisville & Nashville class M-1

The L&N used a total of 42 Berkshires which were commonly known as “Big Emmas”. They were similar to the Berkshires designed by the Van Sweringens for the Nickel Plate Road and also used by other railroads, but they were an independent design that was first built by Baldwin. Designed to take advantage of all modern features used in steam locomotives, they were more complex and more expensive than the other locomotives of the same wheel arrangement. In 1942, 14 were delivered by Baldwin, followed by six more two years later. Lima delivered 22 in 1949 which were somewhat heavier.

The boilers had a combustion chamber, thermic syphons, arch tubes and a Worthington feed water heater. Extensive use of roller bearings in many places reduced friction and consumption. The Lima locomotives were delivered with boosters and the Baldwin locomotives were later retrofitted. Altogether, they were more powerful, but more economical than the previous Mikados. In the result, they could haul coal trains of up to 9,500 tons. Since the Berkshire was a good all-rounder, some were used in passenger service. The first ones were already retired and replaced by diesel locomotives in 1950, only one year after the Lima batch was delivered. The last ones were gone in 1956 and all locomotives were scrapped, only two tenders survived.