UIC classification
Encyclopedia
The UIC classification of locomotive axle arrangements describes the wheel arrangement
of locomotive
s, multiple unit
s and tram
s. It is set out in the International Union of Railways
(UIC) "Leaflet 650 - Standard designation of axle arrangement on locomotives and multiple-unit sets". It is used in much of the world. The United Kingdom
used a related scheme. The United States
uses the simplified AAR wheel arrangement
for modern locomotives.
It is a more versatile system than Whyte notation
, making fewer assumptions about locomotive layout. Some locomotives are impossible to classify using Whyte notation, but UIC classification handles them easily. The UIC classification is also much more suited to diesel
and electric locomotive
s.
Upper-case letters: the number of consecutive driving axles, starting at A for a single axle. C thus indicates three consecutive pairs of driving wheels.
Numbers: consecutive non-driving axles, starting with 1 for a single axle.
Lower-case "o", suffixing the driving wheel letter: axles are individually driven by electric traction motors
.
Prime sign
" ′ ": the axles are mounted on a bogie
.
Plus sign "+": the locomotive or multiple unit consists of permanently coupled and mechanically separated individual vehicles.
Brackets: groups letters and numbers describing the same bogie. For example, (A1A) indicates a three-axle bogie with the outer two axles driven. When brackets are used a prime is not needed to indicate a bogie. Mallet locomotives can be indicated by bracketing the front power unit — for example, the Union Pacific Big Boy
, 4-8-8-4 in Whyte notation, is (2′D)D2′ in UIC notation.
Garratt
-type locomotives are indicated by bracketing or placing plus signs between all individual units.
Other suffixes:
The most common wheel arrangements in modern locomotives are Bo′Bo′ and Co′Co′.
BB
B′B′
Bo′(A1A)
Bo′Bo′
Bo′Bo′Bo'
C′C′
Co′Co′
2Co'Co2′
D
1′D1′
E
2′D1′h3S
1′E1′h2Gt
1′Dn4vP
D′Dh4vtG
. The Southern Railway
used a system modified from the UIC method. Oliver Bulleid
, the Chief Mechanical Engineer, numbered his 4-6-2 Battle of Britain class Pacifics 21C XXX, referring to leading wheels, trailing wheels and finally powered wheels. The UIC classification for such a locomotive is 2′C1′, Whyte 4-6-2.
:Category:Locomotives by wheel arrangement
Wheel arrangement
In rail transport, a wheel arrangement is a system of classifying the way in which wheels are distributed beneath a locomotive.. Several notations exist to describe the wheel assemblies of a locomotive by type, position, and connections, with the adopted notations varying by country...
of locomotive
Locomotive
A locomotive is a railway vehicle that provides the motive power for a train. The word originates from the Latin loco – "from a place", ablative of locus, "place" + Medieval Latin motivus, "causing motion", and is a shortened form of the term locomotive engine, first used in the early 19th...
s, multiple unit
Multiple unit
The term multiple unit or MU is used to describe a self-propelled carriages capable of coupling with other units of the same or similar type and still being controlled from one driving cab. The term is commonly used to denote passenger trainsets consisting of more than one carriage...
s and tram
Tram
A tram is a passenger rail vehicle which runs on tracks along public urban streets and also sometimes on separate rights of way. It may also run between cities and/or towns , and/or partially grade separated even in the cities...
s. It is set out in the International Union of Railways
International Union of Railways
The UIC , or International Union of Railways, is an international rail transport industry body.- Brief history :The railways of Europe originated as separate concerns. There were many border changes after World War I and the Treaty of Versailles. Colonial railways were the responsibility of the...
(UIC) "Leaflet 650 - Standard designation of axle arrangement on locomotives and multiple-unit sets". It is used in much of the world. The United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
used a related scheme. The United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
uses the simplified AAR wheel arrangement
AAR wheel arrangement
The AAR wheel arrangement system is a method of classifying locomotive wheel arrangements that was developed by the Association of American Railroads. It is essentially a simplification of the European UIC classification, and it is widely used in North America to describe diesel and electric...
for modern locomotives.
It is a more versatile system than Whyte notation
Whyte notation
The Whyte notation for classifying steam locomotives by wheel arrangement was devised by Frederick Methvan Whyte and came into use in the early twentieth century encouraged by an editorial in American Engineer and Railroad Journal...
, making fewer assumptions about locomotive layout. Some locomotives are impossible to classify using Whyte notation, but UIC classification handles them easily. The UIC classification is also much more suited to diesel
Diesel locomotive
A diesel locomotive is a type of railroad locomotive in which the prime mover is a diesel engine, a reciprocating engine operating on the Diesel cycle as invented by Dr. Rudolf Diesel...
and electric locomotive
Electric locomotive
An electric locomotive is a locomotive powered by electricity from overhead lines, a third rail or an on-board energy storage device...
s.
German classification
UIC classification is also known as German classification.Structure
Whereas the Whyte notation counts wheels, the UIC notation counts axles.Upper-case letters: the number of consecutive driving axles, starting at A for a single axle. C thus indicates three consecutive pairs of driving wheels.
Numbers: consecutive non-driving axles, starting with 1 for a single axle.
Lower-case "o", suffixing the driving wheel letter: axles are individually driven by electric traction motors
Traction motor
Traction motor refers to an electric motor providing the primary rotational torque of a machine, usually for conversion into linear motion ....
.
Prime sign
Prime (symbol)
The prime symbol , double prime symbol , and triple prime symbol , etc., are used to designate several different units, and for various other purposes in mathematics, the sciences and linguistics...
" ′ ": the axles are mounted on a bogie
Bogie
A bogie is a wheeled wagon or trolley. In mechanics terms, a bogie is a chassis or framework carrying wheels, attached to a vehicle. It can be fixed in place, as on a cargo truck, mounted on a swivel, as on a railway carriage/car or locomotive, or sprung as in the suspension of a caterpillar...
.
Plus sign "+": the locomotive or multiple unit consists of permanently coupled and mechanically separated individual vehicles.
Brackets: groups letters and numbers describing the same bogie. For example, (A1A) indicates a three-axle bogie with the outer two axles driven. When brackets are used a prime is not needed to indicate a bogie. Mallet locomotives can be indicated by bracketing the front power unit — for example, the Union Pacific Big Boy
Union Pacific Big Boy
Big Boy was the name of the Union Pacific Railroad's 4000-class 4-8-8-4 articulated steam locomotives, built between 1941 and 1944 by American Locomotive Company...
, 4-8-8-4 in Whyte notation, is (2′D)D2′ in UIC notation.
Garratt
Garratt
A Garratt is a type of steam locomotive that is articulated in three parts. Its boiler is mounted on the centre frame, and two steam engines are mounted on separate frames, one on each end of the boiler. Articulation permits larger locomotives to negotiate curves and lighter rails that might...
-type locomotives are indicated by bracketing or placing plus signs between all individual units.
Other suffixes:
- h: Superheated Steam (German: Heißdampf)
- n: Saturated Steam (German: Nassdampf)
- v: Compound (German: Verbund)
- Turb: Turbine
- number: number of cylinders
- t: Tank locomotiveTank locomotiveA tank locomotive or tank engine is a steam locomotive that carries its water in one or more on-board water tanks, instead of pulling it behind it in a tender. It will most likely also have some kind of bunker to hold the fuel. There are several different types of tank locomotive dependent upon...
- G: Freight (German: Güterzug - freight train). Also used to indicate shunting locomotives
- P: Passenger (German: Personenzug - passenger train)
- S: Fast passenger (German: SchnellzugSchnellzugA Schnellzug is an express train in German-speaking countries, where it refers to trains that do not stop at all stations along a line. The term is used both generically and also as a specific train type...
- express train)
The most common wheel arrangements in modern locomotives are Bo′Bo′ and Co′Co′.
Examples
(A1A)(A1A)- Two bogies or wheel assemblies under the unit. Each bogie has one powered axle, one idle axle, and one more powered axle, to provide better load distribution and reduce the wheel load on the track. All powered axles are individually driven by traction motors.
BB
- Four powered axles all mounted in the locomotive's frame, driven in pairs; i.e. each pair of axles is connected by driving rods or gears. Compare with "D" below.
B′B′
- Two bogies or wheel assemblies under the unit. Each truck has two powered axles, connected by driving rods or gears. Three-quarters of all modern locomotives (as well as the power cars of self-propelled trains) are configured in either this or the "Bo′-Bo′" arrangement.
Bo′(A1A)
- Two trucks or wheel assemblies. The "Bo′" truck is under one end of the unit, and has two powered axles, while the "(A1A)" truck under the other end of the unit has one powered axle, one idle axle, and another powered axle. All powered axles are individually driven by traction motors.
Bo′Bo′
- Two bogies or wheel assemblies under the unit. Each truck has two powered axles individually driven by traction motors. Three-quarters of all modern locomotives (as well as the power cars of self-propelled trains) are configured in either this or the "B′B′" arrangement. Many types of tramTramA tram is a passenger rail vehicle which runs on tracks along public urban streets and also sometimes on separate rights of way. It may also run between cities and/or towns , and/or partially grade separated even in the cities...
use this arrangement. See also: Bo-BoBo-BoA Bo-Bo or Bo′Bo′ is a locomotive with two independent four-wheeled bogies with all axles powered by individual traction motors...
.
Bo′Bo′Bo'
- Three bogies or wheel assemblies under the unit. Each truck has two powered axles individually driven by traction motors. See also: Bo-Bo-BoBo-Bo-Bothumb|Italian articulated Bo-Bo-Bo [[FS Class E656|E656]] locomotive, [[Rome]], June 2, 2006.A Bo-Bo-Bo in UIC classification is a locomotive with three independent two-axle bogies with all axles powered...
.
C′C′
- Two bogies or wheel assemblies under the unit. Each truck has three powered axles, connected by driving rods or gears.
Co′Co′
- Two bogies or wheel assemblies under the unit. Each truck has three powered axles individually-driven by traction motors. See also: Co-Co.
2Co'Co2′
- A locomotive with two bogieBogieA bogie is a wheeled wagon or trolley. In mechanics terms, a bogie is a chassis or framework carrying wheels, attached to a vehicle. It can be fixed in place, as on a cargo truck, mounted on a swivel, as on a railway carriage/car or locomotive, or sprung as in the suspension of a caterpillar...
s. These have 2 leading axles and 3 individually powered axles. A number of Japanese electric locomotives used this wheel arrangement, including the JNR Class EF58JNR Class EF58The EF58 is a class of Japanese 2-C+C-2 wheel arrangement electric locomotives. 172 locomotives were built between 1946 and 1958.-The later years:In 1984, 64 out of 172 EF58 locos built were still in service or temporary storage...
.
D
- Four powered axles, connected by driving rods or gears, all mounted in the locomotive's frame (Whyte notation: 0-8-00-8-0Under the Whyte notation for the classification of steam locomotives, 0-8-0 represents the wheel arrangement of no leading wheels, eight powered and coupled driving wheels on four axles, and no trailing wheels...
).
1′D1′
- One leadingLeading wheelThe leading wheel or leading axle of a steam locomotive is an unpowered wheel or axle located in front of the driving wheels. The axle or axles of the leading wheels are normally located in a truck...
idle (non-driven) axle mounted in a bogie, four driven axles mounted in the frame and connected by driving rods or gears, followed one trailingTrailing wheelOn a steam locomotive, a trailing wheel or trailing axle is generally an unpowered wheel or axle located behind the driving wheels. The axle of the trailing wheels was usually located on a trailing truck...
idle axle mounted in a bogie (Whyte notation: 2-8-22-8-2Under the Whyte notation for the classification of steam locomotives, 2-8-2 represents the wheel arrangement of two leading wheels on one axle , eight powered and coupled driving wheels on four axles, and two trailing wheels on one axle...
).
E
- Five powered axles, mounted in the locomotive's frame (Whyte notation: 0-10-00-10-0Under the Whyte notation for the classification of steam locomotives, 0-10-0 represents the wheel arrangement of no leading wheels, ten powered and coupled driving wheels on five axles, and no trailing wheels...
).
2′D1′h3S
- Two front leading axles grouped in a bogie, four driving axles, one trailing axle in a bogie, simple steam expansion, superheated steam, three-cylinders, for fast trains.
1′E1′h2Gt
- One front leading axle in a bogie, five driving axles, one rear trailing axle, simple steam expansion, superheated steam, two-cylinder machine, for freight trains, tank engine.
1′Dn4vP
- One front leading axle in a bogie, four driving axles, saturated steam, four-cylinder machine, compound (double steam expansion), for passenger trains.
D′Dh4vtG
- No front leading axle, four driving axles in a bogie, four more driven axles mounted in the frame (Mallet locomotive), superheated steam, four-cylinder machine, compound (double steam expansion), tank locomotive, for freight trains.
United Kingdom
Standard practice in the United Kingdom was to use the Whyte notationWhyte notation
The Whyte notation for classifying steam locomotives by wheel arrangement was devised by Frederick Methvan Whyte and came into use in the early twentieth century encouraged by an editorial in American Engineer and Railroad Journal...
. The Southern Railway
Southern Railway (Great Britain)
The Southern Railway was a British railway company established in the 1923 Grouping. It linked London with the Channel ports, South West England, South coast resorts and Kent...
used a system modified from the UIC method. Oliver Bulleid
Oliver Bulleid
Oliver Vaughan Snell Bulleid was a British railway and mechanical engineer best known as the Chief Mechanical Engineer of the Southern Railway between 1937 and the 1948 nationalisation, developing many well-known locomotives.- Early life and Great Northern Railway :He was born in Invercargill,...
, the Chief Mechanical Engineer, numbered his 4-6-2 Battle of Britain class Pacifics 21C XXX, referring to leading wheels, trailing wheels and finally powered wheels. The UIC classification for such a locomotive is 2′C1′, Whyte 4-6-2.
See also
- AAR wheel arrangementAAR wheel arrangementThe AAR wheel arrangement system is a method of classifying locomotive wheel arrangements that was developed by the Association of American Railroads. It is essentially a simplification of the European UIC classification, and it is widely used in North America to describe diesel and electric...
- Swiss locomotive and railcar classification
- Wheel arrangementWheel arrangementIn rail transport, a wheel arrangement is a system of classifying the way in which wheels are distributed beneath a locomotive.. Several notations exist to describe the wheel assemblies of a locomotive by type, position, and connections, with the adopted notations varying by country...
- Whyte notationWhyte notationThe Whyte notation for classifying steam locomotives by wheel arrangement was devised by Frederick Methvan Whyte and came into use in the early twentieth century encouraged by an editorial in American Engineer and Railroad Journal...
:Category:Locomotives by wheel arrangement
- International Union of RailwaysInternational Union of RailwaysThe UIC , or International Union of Railways, is an international rail transport industry body.- Brief history :The railways of Europe originated as separate concerns. There were many border changes after World War I and the Treaty of Versailles. Colonial railways were the responsibility of the...
- UIC identification marking for tractive stockUIC identification marking for tractive stockSince the beginning of 2007 all newly authorised railway locomotives or other traction units, at least in Europe, have been given a twelve-digit number. This makes the locomotive or railcar clearly identifiable from an EU-wide list of registered railway vehicles and which follows the UIC Code of...
- UIC classification of railway coachesUIC classification of railway coachesRailway coaches are classified under an international system developed by the UIC. This UIC classification of railway coaches replaced earlier national classification schemes in many countries, such as Germany. The coach class is expressed as a combination of letters. It is sometimes followed, for...
- UIC classification of goods wagonsUIC classification of goods wagonsThis list contains the UIC classification of goods wagons and their meanings. The description is made up of a class letter and usually several code letters ....
- List of UIC country codes