The Louisville & Nashville Railroad bought a total of forty-two "Berkshire" type locomotives in three orders. The first order went to the Baldwin Locomotive Works for fourteen locomotives, which were delivered in 1942 and designated as Class M-1. The first ten of these locomotives, with road numbers 1950 through 1959, were assigned to freight service. The other four, with road numbers 1960 through 1963, pulled passenger trains between Cincinnati, Ohio and Corbin, Kentucky during the World War II years.
The second order was given to Baldwin, which delivered six more Class M-1 "Berkshires" in 1944. This group was assigned road numbers 1964 through 1969. All twenty of these Baldwin built 2-8-4 had 69" diameter drivers, 25" x 32" cylinders, a 265 psi boiler pressure, they exerted 65,290 pounds of tractive effort and each weighed 447,200 pounds.
The third order went to the Lima Locomotive Works for twenty-two locomotives which were delivered in 1949 and assigned road numbers 1970 through 1991. These locomotives had 69" diameter drivers, 25" x 32" cylinders, a 265 psi boiler pressure, they exerted 65,290 pounds of tractive effort and each weighed 448,100 pounds. This order was the next to last order Lima would receive for steam locomotives. The last order would come from the NYC&StL.
The L&N's Class M-1 locomotives had the distinction of being the most expensive "Berkshire" type locomotives made. The designers included every improvement and feature known to the steam locomotive builder's craft.
There are no surviving L&N 2-8-4 "Berkshire" type locomotives. However, there are two tenders that have survived. They are the tenders from number 1966 now at the Southern Railway Museum in Duluth, GA and the tender from number 1985 at the Kentucky Railway Museum in New Haven, KY.
Class M-1 (Locobase 49)
Data from tables and diagram in the 1947 Locomotive Cyclopedia and L&N 3 1956 Locomotive Diagrams supplied in August 2013 by Allen Stanley from his extensive Raildata collection.
Baldwin works numbers were 64605-64618 in 1942, 64723-64726, 70178-70179 in 1944.
Lima works numbers for 1970-1991 were 9349-9350 in January 1949, 9351-9354 in February, 9355-9358 in March, 9359-9363 in April, 9364-9366 in May, 9367-9370 in June.
Built by Baldwin in 1942 and 1944 and by Lima in 1949, these engines were the epitome of the North American fast freight locomotive at the end of the steam era.
One long-time engineer noted that the "Big Emmas" could handle passenger and freight service and that they were very quiet because of the extensive use of roller bearings. Charles B.Castner (in Drury, 1993), compares them to the road's 2-8-2s: "Vastly higher boiler capacity, larger fireboxes, cast steel frames and cylinders, roller bearings, and 12-wheel tenders gave the M-1s greater horsepower to work heavy trains at higher speeds on 12% less fuel."
Firebox had a short combustion chamber as well as three thermic syphons that contributed 103.5 sq ft (9.6 sq m) and two arch tubes that added 21.5 sq ft (2 sq m) to direct heating surface area. Piston valves measured 14" (356 mm) in diameter. Boiler fitted with Worthington Type 5 1/2 SA feed water heater.
On the Eastern Kentucky line, notes Castner, these engines regularly managed 124-car, 9,500-ton coal trains alone between Neon and DeCoursey, using helpers only on the Jackson and Ravenna grades. On the Cumberland Valley and Cincinatti Divisions, the tonnage rating was 8,300.
The 1942 Baldwins were sent to the ferro-knacker in December 1950. The 1944 and 1949 engines were scrapped in 1956.