A selection of early 20th century locomotive types according to their Whyte notation and their comparative size

The Whyte notation for classifying steam locomotives by wheel arrangement was devised by Frederick Methvan Whyte and came into use in the early 20th century. Whyte's system counts the number of leading wheels, then the number of driving wheels, and finally the number of trailing wheels, this being the common pattern of the conventional steam locomotive. Image File history File links Download high resolution version (618x1767, 202 KB)Locomotives of different types. ... Image File history File links Download high resolution version (618x1767, 202 KB)Locomotives of different types. ... Great Western Railway No. ... Locomotive wheel arrangement is how the wheels of the locomotive are arranged by type, position, and connections. ... Frederick Methvan Whyte (1865 – 1941) was a mechanical engineer of Dutch background who worked for the New York Central railroad in the United States. ... (19th century - 20th century - 21st century - more centuries) Decades: 1900s 1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s As a means of recording the passage of time, the 20th century was that century which lasted from 1901–2000 in the sense of the Gregorian calendar (1900–1999 in the... On a steam locomotive, a leading wheel or leading axle is an unpowered wheel or axle located in front of the driving wheels. ... On a steam locomotive, a driving wheel is a powered wheel which is driven by the locomotives pistons (or turbine, in the case of a steam turbine locomotive). ... The trailing wheels (boxed) on a 4-6-2 locomotive. ...

Thus, a locomotive with two leading axles (and thus four wheels) in front, then three driving axles (six wheels) and followed by one trailing axle (two wheels) is classified as a 4-6-2. An axle is a central shaft for a rotating wheel or gear. ... The Pennsylvania Railroads class K4s, a well known 4-6-2 type. ...

It's important to stress that wheels, not axles, are what is counted in this system. Other classification schemes in use elsewhere (like the UIC classification) count axles. The UIC classification is a comprehensive system for describing the wheel arrangements of locomotives. ...

The system had to be extended with the advent of articulated locomotives. The scheme generally adopted is that locomotives such as Garratts, where there are, in effect, two separate locomotives joined by a common boiler, are classified by using a plus sign in between the arrangements of each engine. Thus, a 'double Pacific' type Garratt is a 4-6-2+2-6-4. An articulated locomotive is a steam locomotive with one or more engine units which can move relative to the main frame. ... A locomotive (from lat. ... Garratt on the Welsh Higland Railway South African Garratt Diagram of a Garratt locomotive A Garratt is a type of steam locomotive that is articulated, normally in three parts. ... A boiler is a closed vessel in which water or other fluid is heated under pressure. ...

Simpler articulated types such as Mallets, where there are no unpowered axles in between powered axles, are just written by adding extra numbers in the middle; each number represents a grouping of wheels. Thus a Big Boy is written under this modified Whyte notation as a 4-8-8-4; there are two leading axles, one group of four driving axles, another group of four driving axles, and then two trailing axles. A typical European Mallet type, a narrow gauge 0-4-4-2 tank locomotive for a mountain railway (in this case, the RhB in Switzerland). ... Big Boy was the nickname universally applied to the Union Pacific Railroads twenty-five 4000 class 4-8-8-4 steam locomotives built between 1941 and 1944 by Alco. ...

In addition the suffix 'T' is often used to indicate a tank locomotive (otherwise, a tender locomotive is assumed). In British practice, this is sometimes extended to indicate what type of tank locomotive. When this is done, a plain 'T' means side tank, 'ST' means saddle tank, PT means pannier tank and WT stands for well tank. Where a 'T' suffix is followed by '+T', this indicates a tank locomotive that has a tender for additional coal or water capacity. A tank locomotive (occasionally tank engine) is a steam locomotive that carries its own fuel and water with it, instead of pulling it behind it in a tender. ... A British tender locomotive Steam locomotives often haul a tender, which is a special railroad car designed to hold the locomotives fuel (wood or coal) and water. ... A tank locomotive (occasionally tank engine) is a steam locomotive that carries its own fuel and water with it, instead of pulling it behind it in a tender. ... A tank locomotive (occasionally tank engine) is a steam locomotive that carries its own fuel and water with it, instead of pulling it behind it in a tender. ... A tank locomotive (occasionally tank engine) is a steam locomotive that carries its own fuel and water with it, instead of pulling it behind it in a tender. ... A tank locomotive (occasionally tank engine) is a steam locomotive that carries its own fuel and water with it, instead of pulling it behind it in a tender. ...

The limitations of the Whyte system for classifying locomotives that did not fit the standard steam locomotive pattern led to the design of other forms of classification. Most commonly used in Europe is the UIC classification scheme, based on German practice, which can more completely define the exact layout of a locomotive. The UIC classification is a comprehensive system for describing the wheel arrangements of locomotives. ...

In American (and to a lesser extent British) practice, most wheel arrangements in common use were given names.

Here is a list of the most common wheel arrangements: in the illustration, which should be read left to right, with the front of the locomotive to the left, small o is a carrying axle, and a big O is a driving axle.

Garratts are almost always two identical locomotive frames back-to-back, and are thus called Double Pacifics, Double Northerns etc. In Whyte notation, a 0-2-2 is a railroad steam locomotive that has two coupled driving wheels followed by two and two trailing wheels, with no leading wheels . ... In the Whyte notation, a 2-2-0 is a railroad steam locomotive that has one unpowered leading axle and one powered driving axle. ... Under the Whyte notation for the classification of steam locomotives, a 2-2-2 locomotive has two leading wheels, two driving wheels and two trailing wheels. ... In Whyte notation, a 2-2-4 is a railroad steam locomotive that has two leading wheels followed by two coupled driving wheels and four trailing wheels. ... The Chicago & Northwestern Railways first locomotive, 4-2-0 Pioneer. ... Under the Whyte notation for the classification of steam locomotives, a 4-2-2 locomotive has four leading wheels arranged in a leading truck, two driving wheels and two trailing wheels. ... In Whyte notation, a 4-2-4 is a steam locomotive that has a four-wheel leading truck, one powered driving axle and a four-wheel unpowered trailing truck. ... In the Whyte notation, a 6-2-0 is a railroad steam locomotive that has an unpowered three-axle leading truck followed by a single powered driving axle. ... Under the Whyte notation for the classification of steam locomotives, 0-4-0 represents one of the simplest possible types, that with two axles and four wheels, all of which are driven. ... In Whyte notation, a 0-4-2 is a railroad steam locomotive that has four coupled driving wheels followed by two trailing wheels, with no leading wheels . ... In Whyte notation, a 0-4-4 is a railroad steam locomotive that has four coupled driving wheels followed by four trailing wheels, with no leading wheels . ... In Whyte notation, a 2-4-0 is a railroad steam locomotive that has two leading wheels followed by two coupled driving wheels, with no trailing wheels. ... 2-4-2 is the Whyte notation for a Columbia-type railroad locomotive. ... 2-4-4 Mason Bogie locomotive #6 on the Boston, Revere Beach and Lynn Railroad as built in 1886. ... Atlantic, Mississippi and Ohio Railroad #87, delivered 1873-10-27 from the Mason Machine Works of Taunton, Massachusetts. ... A 15 gauge 4-4-2 operating on the Riverside and Great Northern Railway in Wisconsin Dells, WI. In the Whyte notation a 4-4-2 is a steam locomotive that has a two-axle leading truck, two powered driving axles and a one-axle trailing truck. ... Under the Whyte notation for the classification of steam locomotives, a 4-4-4 locomotive has four leading wheels arranged in a leading truck, four coupled driving wheels and four trailing wheels in a trailing truck. ... 0-6-0 is also the emergency telephone number in Mexico, similar to the United Statess 9-1-1. ... In Whyte notation, a 0-6-2 is a railroad steam locomotive that has six coupled driving wheels followed by two trailing wheels, with no leading wheels . ... In Whyte notation, a 0-6-4 is a railroad steam locomotive that has six coupled driving wheels followed by four trailing wheels, with no leading wheels . ... SRC 89 working on the daily passenger train in 1993. ... A Pairie type built for the Burlington by Baldwin. ... Under the Whyte notation for the classification of steam locomotives, a 2-6-4 locomotive has two leading wheels, six coupled driving wheels and four trailing wheels in a trailing truck. ... In the Whyte notation for describing steam locomotive wheel arrangement, a 2-6-6 is a locomotive with a two-wheeled leading truck, six driving wheels, and a six-wheeled trailing truck. ... In the Whyte notation, a 4-6-0 is a railroad steam locomotive that has a two-axle leading truck followed by three driving axles. ... The Pennsylvania Railroads class K4s, a well known 4-6-2 type. ... A 4-6-4 locomotive, in the Whyte notation for the classification of steam locomotives, has four leading wheels (generally arranged in a leading truck), six coupled driving wheels and four trailing wheels (often but not always in a trailing truck). ... In the Whyte notation for the wheel arrangement of locomotives (primarily steam locomotives), an 0-8-0 is a locomotive with eight powered driving wheels (thus four powered axles), and neither leading wheels or trailing wheels. ... An 0-8-2, in the Whyte notation for the classification of steam locomotives by wheel arrangement, is a locomotive with no leading wheels, eight driving wheels (4 axles) fixed in a rigid frame, and two trailing wheels (normally mounted in a trailing truck). ... A Chinese-built 2-8-0 on display at the National Railroad Museum in Green Bay, WI, April 26, 2004. ... PRR 520, on display at the Pennsylvania Railroad Museum, Strasburg, Pennsylvania, in 1993. ... In the Whyte notation, a 2-8-4 is a railroad steam locomotive that has one unpowered leading axle followed by four powered driving axles and two unpowered trailing axles. ... In the Whyte notation for describing steam locomotive wheel arrangement, a 2-8-6 is a locomotive with a two-wheel leading truck, eight driving wheels, and a six-wheel trailing truck. ... The , an 1874 0-6-6 Mason Bogie and the first locomotive with Walschaerts valve gear built in the United States. ... Norfolk and Western Railway class M2 4-8-0. ... Union Pacific Railroad class MT-1 4-8-2 #7000. ... The Norfolk & Western Railways Class J locomotive #611, a 1950 product of the railroads own Roanoke, Virginia shops. ... Under the Whyte notation for the classification of steam locomotives, a 4-8-6 locomotive would have had four leading wheels, eight coupled driving wheels and six trailing wheels. ... Lima builders plate, 1918 Lima Locomotive Works manufactured railroad locomotives from the 1870s through the 1950s. ... In Whyte notation a 6-8-6 is a steam locomotive with six unpowered leading wheels arranged into a three-axle leading truck, eight powered driving wheels, and six unpowered trailing wheels arranged into a three-axle trailing truck. ... The single S2, #6200, in a PRR promotional image. ... A rotor of a modern steam turbine, used in a power plant A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into useful mechanical work. ... An 0-10-0 switcher of the Chesapeake & Ohio Railroad. ... An 0-10-2, in the Whyte notation for the classification of steam locomotives by wheel arrangement, is a locomotive with no leading wheels at all, ten driving wheels, and a two-wheel trailing truck. ... This 2-10-0 steam locomotive is a Pennsylvania Railroad class I1s, the most successful class of such locomotives in North America. ... This 2-10-2 locomotive is a Pennsylvania Railroad class N1s. ... ATSF 2-10-4 #5000 Madame Queen awaiting an eastbound train at Ricardo, New Mexico in March, 1943. ... Official language(s) English Capital Denver Largest city Denver Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 8th 269 837 km² 451 km 612 km 0. ... Categories: Defunct railroad companies of the United States | Defunct companies | Defunct railroads | Colorado railroads | Illinois railroads | Iowa railroads | Missouri railroads | Montana railroads | Nebraska railroads | Wisconsin railroads | Wyoming railroads ... Under the Whyte notation for the classification of steam locomotives, a 4-10-0 locomotive has four leading wheels followed by ten driving wheels, with no trailing wheels. ... El Gobernador was a 4-10-0 steam locomotive built by Central Pacific Railroad at the railroads Sacramento, California, shops. ... Under the Whyte notation for the classification of steam locomotives, a 4-10-2 locomotive has four leading wheels, ten driving wheels and two trailing wheels. ... The Southern Pacific Railroad (AAR reporting mark SP) was an American railroad. ... In Whyte notation, a 0-12-0 is a railroad steam locomotive that has twelve coupled driving wheels, with no leading wheels or trailing wheels. ... In Whyte notation for the classification of steam locomotives by wheel arrangement, a 2-12-0 is a locomotive with one pair of unpowered leading wheels, followed by six pairs of powered driving wheels, and no trailing wheels. ... Under the Whyte notation for the classification of steam locomotives, a 2-12-2 locomotive has two leading wheels, twelve driving wheels and two trailing wheels. ... In Whyte notation for the classification of steam locomotives by wheel arrangement, a 2-12-4 is a locomotive with one pair of unpowered leading wheels, followed by six pairs of powered driving wheels, and two pairs of unpowered trailing wheels. ... Union Pacific #9000. ... The Union Pacific Railroad (NYSE: UNP) is the largest railroad in the United States. ... A 4-14-4 locomotive A 4-14-4, in the Whyte notation for the classification of steam locomotives by wheel arrangement, is a locomotive with four leading wheels in a leading truck, fourteen driving wheels (seven axles) in a rigid frame, and two trailing wheels in a trailing truck. ... A duplex locomotive is a steam locomotive that divides the driving force on its wheels by using two pairs of cylinders. ... A 4-4-4-4 steam locomotive, in the Whyte notation for describing locomotive wheel arrangements, has four leading wheels in a leading truck, two sets of four driving wheels, and a four-wheel trailing truck. ... A T1 prototype leaves Chicagos Union Station in February 1943 with the Manhattan Limited to New York. ... The Pennsylvania Railroads lone S1 was the only 6-4-4-6 ever constructed. ... The Pennsylvania Railroads class S1 comprised a single steam locomotive of 6-4-4-6 wheel arrangement in the Whyte notation, the only locomotive of such arrangement ever constructed. ... In Whyte notation, a 4-4-6-4 is a railroad steam locomotive that has four leading wheels followed by four coupled driving wheels, a second set of six driving wheels and four trailing wheels. ... PRR Q2 prototype #6131. ... In Whyte notation, a 4-6-4-4 is a railroad steam locomotive that has four leading wheels followed by six coupled driving wheels, a second set of four driving wheels and four trailing wheels. ... The Pennsylvania Railroads class Q1 comprised a single experimental steam locomotive for freight service, #6130, built in March 1942. ... A typical European Mallet type, a narrow gauge 0-4-4-2 tank locomotive for a mountain railway (in this case, the RhB in Switzerland). ... In the Whyte notation for the classification of steam locomotive wheel arrangement, a 0-4-4-0 is a locomotive with no leading truck, two sets of four driving wheels, and no trailing truck. ... In Whyte notation, 2-4-4-2 refers to a railroad steam locomotive that has two leading wheels followed by four coupled driving wheels, a second set of four coupled driving wheels, and two trailing wheels. ... In Whyte notation, a 0-6-6-0 is a railroad steam locomotive that has two articulated sections, each with six coupled driving wheels, without any leading wheels or trailing wheels. ... In Whyte notation for the classification of steam locomotives by wheel arrangement, a 2-6-6-0 is a locomotive with one pair of unpowered leading wheels, followed by two sets of three pairs of powered driving wheels, and no trailing wheels. ... In Whyte notation, 2-6-6-2 refers to a railroad steam locomotive that has two leading wheels followed by six coupled driving wheels, a second set of six coupled driving wheels, and two trailing wheels. ... Norfolk & Western Class A #1206 displayed at the New York Worlds Fair in 1939. ... The 2-6-6-6 (in Whyte notation) locomotive type has 2 leading wheels and three sets of six driving wheels. ... In Whyte notation, a 4-6-6-2 is a steam locomotive with four leading wheels (two axles) in an unpowered bogie at the front of the locomotive followed by two sets of driving wheels with six wheels each (three axles each), followed by two unpowered trailing wheels (one axle... Southern Pacific Railroads MM-2 class of steam locomotives was Southern Pacifics (SP) only class of 2-6-6-2 locomotives ordered and built as cab forward locomotives. ... In Whyte notation, a 4-6-6-4 is a railroad steam locomotive that has four leading wheels followed by six coupled driving wheels, a second set of six driving wheels and four trailing wheels. ... A 2-6-8-0 locomotive A 2-6-8-0 steam locomotive, in the Whyte notation for describing locomotive wheel arrangements, has two leading wheels in a leading truck, a set of six driving wheels, a set of eight driving wheels, and no trailing truck. ... 0-8-8-0 #8701 of the New York Central Railroad at Detroit, Illinois in 1921. ... 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. ... A USRA standard 2-8-8-2 . 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. ... Duluth, Missabe & Iron Range 2-8-8-4 Yellowstone #229 as preserved. ... Under the Whyte notation for the classification of steam locomotives, a 4-8-8-2 is a Cab Forward type locomotive with four leading wheels, two sets of eight driving wheels, and a two-wheel trailing truck. ... In the Whyte notation for the classification of steam locomotives by wheel arrangement, a 4-8-8-4 is a locomotive with a four-wheel leading truck, two sets of eight driving wheels, and a four-wheel trailing truck. ... Under the Whyte notation for the classification of steam locomotive wheel arrangements, a 2-10-10-2 is a locomotive with two leading wheels, two sets of ten driving wheels, and a pair of trailing wheels. ... Under the Whyte notation for the classification of steam locomotives, a 2-8-8-8-2 has two leading wheels, three sets of eight driving wheels, and two trailing wheels. ... 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 a four trailing wheels. ...

See also

• Wheel arrangement
• UIC classification
• Category:Locomotives by wheel arrangement