A 2-8-8-4 steam locomotive, under the Whyte notation, has two leading wheels, two sets of eight driving wheels, and a four-wheel trailing truck. The type was generally named the Yellowstone, a name given it by the first owner, the Northern Pacific Railway, whose lines ran near Yellowstone National Park. Seventy-two Yellowstone-type locomotives were built for four U.S. railroads.
The AAR wheel arrangement system is a method of classifying locomotive wheel arrangements that was developed by the Association of American Railroads. Essentially a simplification of the European UIC classification, it is widely used in North America to describe diesel and electric locomotives. It is not used for steam locomotives, which use the Whyte notation instead.
In the Whyte notation for classifying the wheel arrangement of steam locomotives, an 0-8-8-0 is a locomotive with two sets of eight driving wheels and neither leading wheels nor trailing wheels. Two sets of driving wheels would give far too long a wheelbase to be mounted in a fixed locomotive frame, so all 0-8-8-0s have been articulated locomotives of the Mallet type, whether simple or compound. In the UIC classification, this arrangement would be, refined to Mallet locomotives, (D)D. The type was sometimes called Angus in North America.
A 2-8-8-2, in the Whyte notation for describing steam locomotive wheel arrangements, is an articulated locomotive with a two-wheel leading truck, two sets of eight driving wheels, and a two-wheel trailing truck. The equivalent UIC classification is, refined to Mallet locomotives, (1'D)D1'. These locomotives usually employ the Mallet principles of articulation—with the rear engine rigidly attached to the boiler and the front engine free to rotate—and compounding. The 2-8-8-2 was a design largely limited to American locomotive builders. The last 2-8-8-2 was retired in 1962 from the N&W's roster, two years past the ending of steam though steam was still used on steel mill lines and other railroads until 1983.
In the Whyte notation for the classification of steam locomotives by wheel arrangement, a 2-8-8-0 is a locomotive with a two-wheel leading truck, two sets of eight driving wheels, and no trailing truck.
The Roanoke Shops is a railroad workshop and maintenance facility in Roanoke, Virginia. Between 1884 and 1953, the shops produced 447 steam locomotives, all for the Norfolk and Western Railway (N&W). The Roanoke Shops build the N&W's famous Big Three class steam locomotives; the 4-8-4 class J, the 2-6-6-4 class A, and the 2-8-8-2 class Y6. In late 1953, the Shops built their final steam locomotive, making it last standard gauge steam locomotive built for revenue service in the United States. In 2020, N&W's successor, Norfolk Southern abandoned the Shops and Genesis Rail Services acquired the property in July 2023.
On a steam locomotive, a trailing wheel or trailing axle is generally an unpowered wheel or axle (wheelset) located behind the driving wheels. The axle of the trailing wheels is usually located in a trailing truck. On some large locomotives, a booster engine was mounted on the trailing truck to provide extra tractive effort when starting a heavy train and at low speeds on gradients.
Under the Whyte notation for the classification of steam locomotives, a 4-8-8-2 is a locomotive with four leading wheels, two sets of eight driving wheels, and a two-wheel trailing truck.
The 2-6-6-6 is an articulated locomotive type with two leading wheels, two sets of six driving wheels and six trailing wheels. Only two classes of the 2-6-6-6 type were built. One was the "Allegheny" class, built by the Lima Locomotive Works. The name comes from the locomotive's first service with the Chesapeake and Ohio Railway beginning in 1941, where it was used to haul loaded coal trains over the Allegheny Mountains. The other was the "Blue Ridge" class for the Virginian Railway. These were some of the most powerful reciprocating steam locomotives ever built, at 7,500 hp, and one of the heaviest at 386 tons for the locomotive itself plus 215 tons for the loaded tender.
Under the Whyte notation for the classification of steam locomotives, a 2-8-8-8-4 has two leading wheels, three sets of eight driving wheels, and four trailing wheels.
The Union Pacific Challengers are a type of simple articulated 4-6-6-4 steam locomotive built by American Locomotive Company (ALCO) from 1936 to 1944 and operated by the Union Pacific Railroad until the late 1950s.
Southern Railway 4501 is a preserved Ms class 2-8-2 "Mikado" type steam locomotive built in October 1911 by the Baldwin Locomotive Works in Philadelphia, Pennsylvania as the first of its wheel arrangement type for the Southern Railway (SOU). In 1948, the locomotive was retired from the SOU in favor of dieselization and was sold to the shortline Kentucky and Tennessee Railway (K&T) in Stearns, Kentucky to haul coal trains.
The Norfolk and Western class J was a class of fourteen 4-8-4 "Northern" streamlined steam locomotives built by the Norfolk and Western Railway (N&W) at its Roanoke Shops in Roanoke, Virginia between 1941 and 1950. They performed flawlessly, making them the most powerful 4-8-4 steam locomotives ever produced. The class Js, along with class A and Y6 freight locomotives were the N&W's "Big Three" representing the pinnacles of steam technology.
Norfolk and Western 1218 is a preserved four-cylinder simple articulated 2-6-6-4 steam locomotive, built in June 1943 by the Norfolk and Western's (N&W) Roanoke Shops in Roanoke, Virginia as part of the N&W's class "A" fleet of fast freight locomotives. It was retired from regular revenue service in July 1959, and was later restored by Norfolk Southern for excursion service for their steam program, pulling excursions throughout the eastern United States from 1987 to 1991. It is currently on display at the Virginia Museum of Transportation in Roanoke, Virginia.
Norfolk & Western 2156 is a four-cylinder compound articulated class "Y6a" "Mallet" type steam locomotive with a 2-8-8-2 wheel arrangement. The Norfolk & Western Railway built it in 1942 at its Roanoke Shops in Roanoke, Virginia as a member of the N&W's Y6a class. It is the strongest-pulling extant steam locomotive in the world, although it is not operational. It was retired from regular rail service in July 1959 and is now owned by the National Museum of Transportation in St. Louis, Missouri.
A triplex locomotive is a steam locomotive that divides the driving force on its wheels by using three pairs of cylinders powering three sets of driving wheels. Inevitably any such locomotive will be articulated. All the examples that have been produced were of the Mallet type but with one extra set of driving wheels under the tender.
The Norfolk and Western M, M1 and M2 Classes were a series of 4-8-0 steam locomotives owned and operated by the Norfolk and Western Railway (N&W). The M Classes were primarily assigned to pull the N&W's mainline freight trains, but following the introduction of the railway's Y Class 2-8-8-2's, the M Classes were reassigned to short line freight service.
Norfolk and Western 611, also known as the "Spirit of Roanoke" and the "Queen of Steam", is a Norfolk and Western (N&W) class J 4-8-4 "Northern" streamlined steam locomotive built in May 1950 by the N&W's Roanoke Shops in Roanoke, Virginia. It was one of the last mainline passenger steam locomotives built in the United States and represents the pinnacle of steam locomotive technology.
The Norfolk and Western A was a class of 43 2-6-6-4 steam locomotives built by the railroad's own Roanoke Shops between 1936 and 1950 and operated until the late 1950s. The locomotives hauled fast and heavy freight trains for the railroad and only one has been preserved, No. 1218.
The Chesapeake and Ohio H-8 was a class of 60 2-6-6-6 steam locomotives built by the Lima Locomotive Works in Lima, Ohio between 1941 and 1948, operating until the mid 1950s. The locomotives were among the most powerful steam locomotives ever built and hauled fast, heavy freight trains for the railroad. Only two units were preserved; Nos. 1601 and 1604.
