AAR wheel arrangement
Encyclopedia
The AAR wheel arrangement system is a method of classifying locomotive (or unit) wheel arrangement
s 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 locomotive
s. It is not used for steam locomotive
s; instead, the Whyte notation
is used.
The AAR system counts axles instead of wheels. Letters refer to powered axles, and numbers to unpowered (or idler) axles. "A" refers to one powered axle, "B" to two powered axles in a row, "C" to three powered axles in a row, and "D" to four powered axles in a row. "1" refers to one idler axle, and "2" to two idler axles in a row. A dash ("–") separates trucks
, or wheel assemblies. A plus sign ("+") refers to articulation.
) cars.
.
800 hp railcar, six of which were built by the St. Louis Car Company exclusively for the Southern Railway
in 1939.
s built by ALCO/ACF in 1935 and 1937 for use with the Rebel
streamliners.
800 hp railcar, six of which were built by the St. Louis Car Company exclusively for the Southern Railway
in 1939.
for the General Pershing Zephyr
.
in 1948.
s, which were passenger locomotives, and the dual service FM Erie-built
. BNSF is scheduled to take delivery of ES44C4 locomotives with this type of truck in 2009.
under the rear of the unit. The only example to date of this arrangement was a single experimental EMD SDP45
.
. This arrangement is sometimes referred to as 0-4-0
, the Whyte notation
equivalent.
locomotives built by EMD in 1956.
locomotives built by Baldwin
in 1956 and 1957 for use with Pullman-Standard Train-X equipment.
(most passenger units) built from 1950–1955, and the EMD FL9
.
, as well as switching
. Examples include the EMD GP (General Purpose) units.
locomotives.
.
GE boxcab electrics of 1923 are examples of this wheel arrangement.
and DD2
electric locomotive
s used this arrangement.
"Boxcab" electrics.
s. An example would be the General Electric U50
, built from 1963-1965. The 4500 horsepower (3.4 MW) turbine locomotives built by GE
for Union Pacific also used this arrangement. The EFVM railway of Brazil
uses narrow gauge GE "BB" locomotives with this arrangement, both with "standard" and wide cabs. A GE BB40-9W
, for instance, is a wide cab GE Dash 9-40CW
series 4000 hp locomotive with a B+B-B+B wheel arrangement.
. In most cases the locomotive is articulated over the span bolster. The Union Pacific's M-10002
is an example of this type. This arrangement also includes locomotives made of two permanently coupled B-B units, such as some EMD FT
units which had a solid drawbar connecting two units instead of the typical couplers.
, the Whyte notation
equivalent.
has this wheel arrangement.
and FF2
electric locomotives used this arrangement.
electric locomotives were notable examples of this arrangement.
-fired steam-turbine locomotives built by the Baldwin Locomotive Works for the Chesapeake and Ohio Railway
between 1947 and 1948. This locomotive is sometimes called the M-1.
built by General Electric
for Union Pacific. These locomotives consisted of two permanently-coupled C-C units.
s. This arrangement was used on the Jawn Henry coal
-fired steam-turbine locomotive built by the Baldwin Locomotive Works
for the Norfolk & Western Railway in May, 1954.
T-Motor
electric locomotives, for the Grand Central Terminal
electrification, used this arrangement.
R1
electric locomotive and Western Australian Government Railways
X class
used this arrangement.
DR-12-8-1500/2 "Centipede" diesel locomotive
s and the GE
"Little Joe
" electric locomotive
s.
electric locomotives used by the Milwaukee Road used this arrangement.
's EL-2B
electric locomotives.
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...
s that was developed by the Association of American Railroads
Association of American Railroads
The Association of American Railroads is an industry trade group representing primarily the major freight railroads of North America . Amtrak and some regional commuter railroads are also members...
. It is essentially a simplification of the European UIC classification
UIC classification
The UIC classification of locomotive axle arrangements describes the wheel arrangement of locomotives, multiple units and trams. It is set out in the International Union of Railways "Leaflet 650 - Standard designation of axle arrangement on locomotives and multiple-unit sets". It is used in much...
, and it is widely used in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
to describe 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. It is not used for steam locomotive
Steam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...
s; instead, the 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...
is used.
The AAR system counts axles instead of wheels. Letters refer to powered axles, and numbers to unpowered (or idler) axles. "A" refers to one powered axle, "B" to two powered axles in a row, "C" to three powered axles in a row, and "D" to four powered axles in a row. "1" refers to one idler axle, and "2" to two idler axles in a row. A dash ("–") separates trucks
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...
, or wheel assemblies. A plus sign ("+") refers to articulation.
1A-A1
"1A-A1" means there are two trucks (or wheel assemblies) under the unit. Each truck has one powered axle, and one idler axle, with the idler axles to the outside. Examples include Budd RDC Diesel MU (DMUDiesel multiple unit
A diesel multiple unit or DMU is a multiple unit train consisting of multiple carriages powered by one or more on-board diesel engines. They may also be referred to as a railcar or railmotor, depending on country.-Design:...
) cars.
1-D
"1-D" means there are two trucks. The "1" truck is under the front of the unit, and has one idler axle. The remaining 4 axles are rigidly mounted to the frame behind this lead truck . The only known examples are a series of diesel locomotives built and owned by the Texas Mexican RailwayTexas Mexican Railway
The Texas Mexican Railway is a class 1 railroad that operates as a subsidiary of Kansas City Southern Railway in Texas. It is often referred to as the Tex-Mex, or TexMex Railway....
.
2-A1A
"2-A1A" means there are two trucks. The "2" truck is under the front of the unit, and has two idler axles in a row. The "A1A" truck is under the rear of the unit, and has one powered axle, one idler axle, and one more powered axle. An example is the FM OP800FM OP800
The OP800 was a lightweight, streamlined railcar built by the St. Louis Car Company in 1939. Fairbanks-Morse supplied the 800 hp, five-cylinder 8 x 10 opposed piston engine prime mover. The units were configured in a highly-unusual 2-A1A wheel arrangement mounted atop a pair of road trucks, and...
800 hp railcar, six of which were built by the St. Louis Car Company exclusively for the Southern Railway
Southern Railway (US)
The Southern Railway is a former United States railroad. It was the product of nearly 150 predecessor lines that were combined, reorganized and recombined beginning in the 1830s, formally becoming the Southern Railway in 1894...
in 1939.
2-B
"2-B" means there are two trucks, or wheel assemblies. The "2" truck is under the front of the unit, and has two idler axles in a row. The "B" truck is under the rear of the unit, and has two powered axles. Examples include the three lightweight power carPower car
A power car is a railroad vehicle that is closely related to the locomotive. What differentiates the two is their construction or their use. A true locomotive can be physically separated from its train and does nothing but provide propulsion . A power car, on the other hand, is frequently an...
s built by ALCO/ACF in 1935 and 1937 for use with the Rebel
Rebel (train)
The Gulf, Mobile and Northern Railroad Rebels were lightweight, streamlined Diesel-electric trains built by American Car and Foundry. The first two trains, purchased in 1935, provided service between New Orleans, Louisiana and Jackson, Tennessee. The third train, purchased in 1937, allowed...
streamliners.
3-A1A
"3-A1A" means there are two trucks. The "3" truck is under the front of the unit, and has three idler axles in a row. The "A1A" truck is under the rear of the unit, and has one powered axle, one idler axle, and one more powered axle. An example is the later built FM OP800FM OP800
The OP800 was a lightweight, streamlined railcar built by the St. Louis Car Company in 1939. Fairbanks-Morse supplied the 800 hp, five-cylinder 8 x 10 opposed piston engine prime mover. The units were configured in a highly-unusual 2-A1A wheel arrangement mounted atop a pair of road trucks, and...
800 hp railcar, six of which were built by the St. Louis Car Company exclusively for the Southern Railway
Southern Railway (US)
The Southern Railway is a former United States railroad. It was the product of nearly 150 predecessor lines that were combined, reorganized and recombined beginning in the 1830s, formally becoming the Southern Railway in 1894...
in 1939.
A1-1A
"A1-1A" means there are two trucks under the unit. Each truck has one powered axle, and one idler axle, with the powered axles to the outside.A1A-2
"A1A-2" means there are two trucks. The "A1A" truck is under the front of the unit, and has one powered axle, one idler axle, and one more powered axle. The "2" truck is under the back of the unit, and has two idler axles in a row. An example is the Silver Charger power carPower car
A power car is a railroad vehicle that is closely related to the locomotive. What differentiates the two is their construction or their use. A true locomotive can be physically separated from its train and does nothing but provide propulsion . A power car, on the other hand, is frequently an...
for the General Pershing Zephyr
General Pershing Zephyr
The General Pershing Zephyr was the ninth of the Chicago, Burlington and Quincy Railroad's Zephyr streamliners, and the last built as an integrated streamliner rather than a train hauled by an EMD E-unit diesel locomotive...
.
A1A-3
"A1A-3" means there are two trucks. The "A1A" truck is under the front of the unit, and has one powered axle, one idler axle, and one more powered axle. The "3" truck is under the back of the unit, and has three idler axles in a row. An example is the Baldwin DR-6-2-10 1000 hp cab unit, only one of which was built for the Chicago and North Western RailwayChicago and North Western Railway
The Chicago and North Western Transportation Company was a Class I railroad in the Midwest United States. It was also known as the North Western. The railroad operated more than of track as of the turn of the 20th century, and over of track in seven states before retrenchment in the late 1970s...
in 1948.
A1A-A1A
"A1A-A1A" means there are two trucks under the unit. Each truck has one powered axle, one idler axle, and one more powered axle. This was to more evenly spread the weight of the locomotive over the track. Examples include the EMD E-units and ALCO PAALCO PA
ALCO PA refers to a family of A1A-A1A diesel locomotives built to haul passenger trains that were built in Schenectady, New York in the United States by a partnership of the American Locomotive Company and General Electric between June, 1946 and December, 1953...
s, which were passenger locomotives, and the dual service FM Erie-built
FM Erie-built
The Erie-built was the first streamlined, cab-equipped dual service diesel locomotive built by Fairbanks-Morse, introduced as direct competition to such models as the ALCO PA and EMD E-unit...
. BNSF is scheduled to take delivery of ES44C4 locomotives with this type of truck in 2009.
A1A-B+B
"A1A-B+B" means there are three trucks. The first truck has three axles, with the center one unpowered. A pair of two-axle trucks, each with both axles powered, are connected by a span bolsterSpan bolster
A span bolster, in rail terminology, is a beam or frame used to link two trucks or bogies so that they can be articulated together and be joined to the locomotive or railroad car at one rotating mounting point...
under the rear of the unit. The only example to date of this arrangement was a single experimental EMD SDP45
EMD SDP45
The EMD SDP45 was a six-axle, C-C, diesel locomotive built by General Motors' Electro-Motive Division of La Grange, Illinois. It was fundamentally a passenger-hauling version of the SD45 on a stretched locomotive frame and with an extended, squared-off long hood at the rear, aft of the radiators,...
.
B
"B" means there are two powered axles under the unit. These axles are not articulated relative to other parts of the locomotive. This arrangement is only used on very small locomotives, such as the EMD Model 40EMD Model 40
The EMD Model 40 was a two-axle diesel-electric locomotive built by Electro-Motive Corporation, and its corporate successor, General Motors' Electro-Motive Division between August 1940 and April 1943. Nicknamed "critters", eleven examples of this locomotive were built. Powered by twin General...
. This arrangement is sometimes referred to as 0-4-0
0-4-0
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 coupled wheels, all of which are driven...
, the 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...
equivalent.
B-1
"B-1" means there are two trucks. The "B" truck is under the front of the unit, and has two powered axles. The "1" truck is under the back of the unit, and has one idler axle. Examples include the three EMD LWT12EMD LWT12
The EMD LWT12 was an experimental diesel locomotive built by General Motors Electro-Motive Division between 1956 and 1958, and designed to pull light high-speed passenger trains...
locomotives built by EMD in 1956.
B-2
"B-2" means there are two trucks. The "B" truck is under the front of the unit, and has two powered axles. The "2" truck is under the back of the unit, and has two idler axles in a row. Examples include the three lightweight RP-210Baldwin RP-210
The RP-210 was a streamlined, locomotive built in 1956 by Baldwin-Lima-Hamilton, specifically to operate with the lightweight, all aluminum, Train-X train produced by Pullman Car Company...
locomotives built by Baldwin
Baldwin Locomotive Works
The Baldwin Locomotive Works was an American builder of railroad locomotives. It was located in Philadelphia, Pennsylvania, originally, and later in nearby Eddystone, Pennsylvania. Although the company was very successful as a producer of steam locomotives, its transition to the production of...
in 1956 and 1957 for use with Pullman-Standard Train-X equipment.
B-A1A
"B-A1A" means there are two trucks. The "B" truck is under the front of the unit, and has two powered axles. The "A1A" truck is under the back of the unit, and has one powered axle, one idler axle, and one more powered axle. Examples include some of the FM C-linersFM Consolidated line
The Consolidated line, or C-line, was a series of diesel-electric railway locomotive designs produced by Fairbanks-Morse and its Canadian licensee, the Canadian Locomotive Company. Individual locomotives in this series were commonly referred to as “C-liners”...
(most passenger units) built from 1950–1955, and the EMD FL9
EMD FL9
The EMD FL9 was a dual-power electro-diesel locomotive, capable of diesel-electric operation and of operation as an electric locomotive powered from a third rail...
.
B-B
"B-B" means there are two identical trucks. Each truck has two powered axles, a currently-popular configuration used in high-speed, low-weight applications, such as intermodal trains, high-speed railHigh-speed rail
High-speed rail is a type of passenger rail transport that operates significantly faster than the normal speed of rail traffic. Specific definitions by the European Union include for upgraded track and or faster for new track, whilst in the United States, the U.S...
, as well as switching
Switcher
A switcher or shunter is a small railroad locomotive intended not for moving trains over long distances but rather for assembling trains ready for a road locomotive to take over, disassembling a train that has been...
. Examples include the EMD GP (General Purpose) units.
B-2-B
"B-2-B" means there are three trucks. The center truck has two unpowered axles and the truck at each end has two powered axles. The locomotive frame must either articulate or allow for significant side play to be provided to the center truck. Examples include the JNR Class DD51JNR Class DD51
The DD51 is a class of Japanese B-2-B wheel arrangement diesel-hydraulic locomotives. 649 locomotives were built between 1962 and 1978 by Kawasaki Sharyō, Hitachi, and Mitsubishi. The class was designed for mainline passenger and freight use with more power than the D51 and a higher maximum speed...
locomotives.
B-B-B
"B-B-B" means there are three trucks. Each truck has two powered axles. The locomotive frame must either articulate or allow for significant side play to be provided to the center truck. See also Bo-Bo-BoBo-Bo-Bo
thumb|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...
.
B+B+B
"B+B+B" means there are three articulated sets of two powered axles each under the unit. The locomotive frame must allow for significant side play to be provided to the center axle set, as well as allowing for end play for the end sets. The ten Mexican RailwayMexican Railway
The Mexican Railway was one of the primary pre-nationalization railways of Mexico. Incorporated in London in September 1864 as the Imperial Mexican Railway to complete an earlier project, it was renamed in July 1867 after the Second French Empire withdrew from Mexico...
GE boxcab electrics of 1923 are examples of this wheel arrangement.
2-B+B-2
"2-B+B-2" means there are two sets of articulated axles under the unit. Within each of these sets, there is a truck with two idler axles, and inboard of it are two powered axles. Two of these articulated sets are placed back to back and connected by a hinge. The PRR DD1PRR DD1
The Pennsylvania Railroad's class DD1 were semi-permanently coupled pairs of third rail direct current electric locomotives built for the railroad's initial New York-area electrification. They operated between Manhattan Transfer and Pennsylvania Station in New York City, and from there to the...
and DD2
PRR DD2
The Pennsylvania Railroad's class DD2 electric locomotive was a single prototype locomotive never placed into series production.It was intended as an improved and simplified GG1 for use on the planned, but never built, extension of the PRR's electrification west of Harrisburg, Pennsylvania.The one...
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 used this arrangement.
2-B+B+B+B-2
"2-B+B+B+B-2" means there are two sets of articulated axles under the unit. Within each of these sets, there is a truck with two idler axles, and inboard of it are two powered axles, hinged to yet another set of two powered axles. Two of these articulated sets are placed back to back and connected by a hinge. Examples include the Milwaukee Road EF-1Milwaukee Road class EP-1, EF-1, EF-2, EF-3, and EF-5
The Chicago, Milwaukee, St. Paul and Pacific Railroad classes EP-1 and EF-1 comprised 42 boxcab electric locomotives built by the American Locomotive Company in 1915. Electrical components were from General Electric. The locomotives were composed of two half-units semi-permanently coupled...
"Boxcab" electrics.
B+B-B+B
"B+B-B+B" means there are four trucks under the unit. Within each truck, there are two powered axles, and pairs of them are connected by span bolsterSpan bolster
A span bolster, in rail terminology, is a beam or frame used to link two trucks or bogies so that they can be articulated together and be joined to the locomotive or railroad car at one rotating mounting point...
s. An example would be the General Electric U50
GE U50
The GE U50 was an eight-axle, diesel locomotive built by GE Transportation Systems. They were twin-engined locomotives, combining two 2,500 hp diesel engines.-Configuration:...
, built from 1963-1965. The 4500 horsepower (3.4 MW) turbine locomotives built by GE
Gê
Gê are the people who spoke Ge languages of the northern South American Caribbean coast and Brazil. In Brazil the Gê were found in Rio de Janeiro, Minas Gerais, Bahia, Piaui, Mato Grosso, Goias, Tocantins, Maranhão, and as far south as Paraguay....
for Union Pacific also used this arrangement. The EFVM railway of Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
uses narrow gauge GE "BB" locomotives with this arrangement, both with "standard" and wide cabs. A GE BB40-9W
GE BB40-9W
The GE BB40-9W is a narrow-gauge version of the popular GE C40-9W locomotive. All 141 examples of this locomotive are owned by the EFVM railroad in Brazil. They are equipped with four B-style trucks, two at each end replacing the conventional C-style trucks. This is necessary because EFVM tracks...
, for instance, is a wide cab GE Dash 9-40CW
GE Dash 9-40CW
The GE Dash 9-40CW is a diesel locomotive that was built by GE Transportation Systems of Erie, Pennsylvania between January 1996 and September 2004. All 1,090 units were built for Norfolk Southern Railway, as road numbers 8889 to 9978. Part of the "Dash 9" locomotive series, these units are...
series 4000 hp locomotive with a B+B-B+B wheel arrangement.
B-B+B-B
"B-B+B-B" means that the locomotive has four trucks. Each truck contains two powered axles. The middle pair of trucks are connected by a span bolsterSpan bolster
A span bolster, in rail terminology, is a beam or frame used to link two trucks or bogies so that they can be articulated together and be joined to the locomotive or railroad car at one rotating mounting point...
. In most cases the locomotive is articulated over the span bolster. The Union Pacific's M-10002
M-10002
The Union Pacific Railroad's M-10002 was a diesel-electric streamliner train built in 1936 by Pullman-Standard with a prime mover from the Winton engine division of General Motors Corporation and General Electric generator, control equipment and traction motors...
is an example of this type. This arrangement also includes locomotives made of two permanently coupled B-B units, such as some EMD FT
EMD FT
The EMD FT was a diesel-electric locomotive produced between November 1939, and November 1945, by General Motors' Electro-Motive Division . All told 555 cab-equipped A units were built, along with 541 cabless booster B units, for a grand total of 1,096 units. The locomotives were all sold to...
units which had a solid drawbar connecting two units instead of the typical couplers.
B-B-B-B
"B-B-B-B" means there are four trucks. Each truck has two powered axles. The locomotive frame must allow for significant side play to be provided to the center trucks.B-B+B-B+B-B
"B-B+B-B+B-B" means that the locomotive has six trucks. Each truck contains two powered axles. The only known locomotives to have this configuration were the two EMD TR3 locomotives made of three permanently coupled B-B units, which had solid drawbars connecting the units instead of the typical couplers.C
"C" means there are three powered axles under the unit. They are not articulated relative to other parts of the locomotive. This arrangement is only used on very small locomotives. This arrangement is sometimes referred to as 0-6-00-6-0
Under the Whyte notation for the classification of steam locomotives, 0-6-0 represents the wheel arrangement of no leading wheels, six powered and coupled driving wheels on three axles, and no trailing wheels...
, the 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...
equivalent.
C-B
"C-B" means there are two trucks. The "C" truck is under the front of the unit, and has three powered axles. The "B" truck is under the rear of the unit, and has two powered axles. The JNR Class DE10JNR Class DE10
The DE10 is a class of Japanese C-B wheel arrangement diesel-hydraulic locomotives. 708 locomotives were built between 1966 and 1978.-DE10-0 subclass:158 DE10-0 locomotives were built with steam heating boilers for passenger use....
has this wheel arrangement.
C-C
"C-C" means there are two identical trucks. Each truck has three powered axles. Examples include the EMD SD (Special Duty) units. This is a currently popular configuration used in low-speed, high-weight applications, such as unit coal trains. See also Co-Co.1-C+C-1
"1-C+C-1" means there are two sets of articulated axles under the unit. Within each of these sets, there is a truck with one idler axle, and inboard of it are three powered axles. Two of these articulated sets are placed back to back and connected by a hinge. The PRR FF1PRR FF1
The Pennsylvania Railroad's class FF1 was an American electric locomotive, a single prototype numbered #3931 and nicknamed "Big Liz" by its crews. It was built in 1917 for the task of hauling freight trains across the Allegheny Mountains, which the PRR planned to electrify; this was never...
and FF2
PRR FF2
The Pennsylvania Railroad's class FF2 was a group of American electric locomotives which comprised eight boxcab units, purchased from the Great Northern Railway in 1956 following the GN's dismantling of its Cascade Tunnel electrification. They had been built by the American Locomotive Company and...
electric locomotives used this arrangement.
2-C+C-2
"2-C+C-2" means there are two sets of articulated axles under the unit. Within each of these sets, there is a truck with two idler axles, and inboard of it are three powered axles. Two of these articulated sets are placed back to back and connected by a hinge. The GG1PRR GG1
The PRR GG1 is a class of electric locomotives that was built for the Pennsylvania Railroad for use in the northeastern United States. A total of 140 GG1s were constructed by its designer General Electric and the Pennsylvania's Altoona Works from 1934 to 1943....
electric locomotives were notable examples of this arrangement.
2+C-C+2
"2+C-C+2" means there are two sets of axles under the unit. Within each of these sets, there is a guiding truck with two idler axles, and inboard of this, and hinged to it, is a truck with three powered axles. The GE Steam turbine-electric locomotives of 1939 were notable examples of this arrangement.2-C1+2-C1-B
"2-C1+2-C1-B" means there are five trucks. Only the first three axles on the four-axle trucks were powered, as were both axles in the last truck; the first and middle trucks had two unpowered axles each. The only examples of this arrangement were three unique coalCoal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
-fired steam-turbine locomotives built by the Baldwin Locomotive Works for the Chesapeake and Ohio Railway
Chesapeake and Ohio Railway
The Chesapeake and Ohio Railway was a Class I railroad formed in 1869 in Virginia from several smaller Virginia railroads begun in the 19th century. Led by industrialist Collis P...
between 1947 and 1948. This locomotive is sometimes called the M-1.
C-C+C-C
"C-C+C-C" means there are four trucks under the unit. Each truck has three powered axles. The only examples of this type were the 8500 horsepower (6.3 MW) turbine locomotivesGas turbine-electric locomotive
A gas turbine - electric locomotive, or GTEL, is a locomotive that uses a gas turbine to drive an electric generator or alternator. The electric current thus produced is used to power traction motors. This type of locomotive was first experimented with during the Second World War, but reached its...
built by General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...
for Union Pacific. These locomotives consisted of two permanently-coupled C-C units.
C+C-C+C
"C+C-C+C" means there are four trucks. Each truck has three powered axles and pairs of them are connected by span bolsterSpan bolster
A span bolster, in rail terminology, is a beam or frame used to link two trucks or bogies so that they can be articulated together and be joined to the locomotive or railroad car at one rotating mounting point...
s. This arrangement was used on the Jawn Henry coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
-fired steam-turbine locomotive built by the Baldwin Locomotive Works
Baldwin Locomotive Works
The Baldwin Locomotive Works was an American builder of railroad locomotives. It was located in Philadelphia, Pennsylvania, originally, and later in nearby Eddystone, Pennsylvania. Although the company was very successful as a producer of steam locomotives, its transition to the production of...
for the Norfolk & Western Railway in May, 1954.
1-D-1
"1-D-1" means there are three trucks under the unit. At either end are trucks with one idler axle; the center truck has four powered axles. The original 1904-1909 NYCNew York Central Railroad
The New York Central Railroad , known simply as the New York Central in its publicity, was a railroad operating in the Northeastern United States...
T-Motor
T-Motor
T-Motor was the name given by the New York Central to its ALCO-GE T1a, T1b, T2a, T2b, and T3a electric locomotives. After the New York Central was merged into Penn Central, Penn Central continued operating them.-History:...
electric locomotives, for the Grand Central Terminal
Grand Central Terminal
Grand Central Terminal —often incorrectly called Grand Central Station, or shortened to simply Grand Central—is a terminal station at 42nd Street and Park Avenue in Midtown Manhattan in New York City, United States...
electrification, used this arrangement.
2-D-2
"2-D-2" means there are three trucks. At either end are trucks with two idler axles; the center truck has four powered axles. The PRRPennsylvania Railroad
The Pennsylvania Railroad was an American Class I railroad, founded in 1846. Commonly referred to as the "Pennsy", the PRR was headquartered in Philadelphia, Pennsylvania....
R1
PRR R1
The Pennsylvania Railroad's class R1 comprised a single prototype electric locomotive constructed in 1934 by the Baldwin Locomotive Works of Philadelphia, Pennsylvania, USA, with the electrical equipment by Westinghouse....
electric locomotive and Western Australian Government Railways
Western Australian Government Railways
Western Australian Government Railways was most common name of the Western Australian government rail transport authority from 1890 to 1976. It is, in its current form, known as the Public Transport Authority of Western Australia....
X class
WAGR X class
The WAGR X class was a class of 48 diesel electric locomotives built for Western Australian Government Railways by Beyer Peacock and Metropolitan Vickers, at Bowesfield Works, Stockton-on-Tees between 1954 and 1956.-The Crossley engine:...
used this arrangement.
D-D
"D-D" means there are two trucks. Each truck has four powered axles. Examples include the EMD DD units.2-D+D-2
"2-D+D-2" means there are two sets of articulated axles under the unit. Within each of these sets, there is a truck with two idler axles, and inboard of it are four powered axles. Two of these articulated sets are placed back to back and connected by a hinge. Examples include the BaldwinBaldwin Locomotive Works
The Baldwin Locomotive Works was an American builder of railroad locomotives. It was located in Philadelphia, Pennsylvania, originally, and later in nearby Eddystone, Pennsylvania. Although the company was very successful as a producer of steam locomotives, its transition to the production of...
DR-12-8-1500/2 "Centipede" diesel locomotive
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...
s and the GE
Gê
Gê are the people who spoke Ge languages of the northern South American Caribbean coast and Brazil. In Brazil the Gê were found in Rio de Janeiro, Minas Gerais, Bahia, Piaui, Mato Grosso, Goias, Tocantins, Maranhão, and as far south as Paraguay....
"Little Joe
Little Joe (electric locomotive)
The Little Joe is a type of railroad electric locomotive built by General Electric for export to the Soviet Union in 1946. The locomotives had twelve axles, eight of them powered, in a 2-D+D-2 arrangement...
" 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.
B-D+D-B
"B-D+D-B" means there are two sets of articulated axles under the unit. Within each of these sets, there is a truck with two powered axles, and inboard of it are four powered axles. Two of these articulated sets are placed back to back and connected by a hinge. The W1 class of electric locomotives built by General Electric for the Great Northern Railway used this arrangement.1B+D+D+B1
"1B+D+D+B1" means there are four sets of articulated axles under the unit. At each end there is one unpowered axle and two powered axles, hinged to a set of four powered axles. Two of these articulated sets are placed back to back and connected by a hinge. The "Bi-Polar"Milwaukee Road class EP-2
The Milwaukee Road's class EP-2 comprised five electric locomotives built by General Electric in 1919. They were often known as Bipolars, which referred to the bipolar electric motors they used. Among the most distinctive and powerful electric locomotives of their time, they epitomized the...
electric locomotives used by the Milwaukee Road used this arrangement.
(B+B-B+B)+(B+B-B+B)
"(B+B-B+B)+(B+B-B+B)" means there are 2 units, each with 4 trucks in a B+B-B+B wheel arrangement. Example include the Virginian RailwayVirginian Railway
The Virginian Railway was a Class I railroad located in Virginia and West Virginia in the United States. The VGN was created to transport high quality "smokeless" bituminous coal from southern West Virginia to port at Hampton Roads....
's EL-2B
VGN EL-2B
The Virginian Railway's class EL-2B comprised four two-unit electric locomotives with AAR + wheel arrangements. The locomotives were used on the electrified portion of the railroad, from Roanoke, Virginia to Mullens, West Virginia...
electric locomotives.
See also
Locomotives by wheel arrangement- Swiss locomotive and railcar classification
- UIC classificationUIC classificationThe UIC classification of locomotive axle arrangements describes the wheel arrangement of locomotives, multiple units and trams. It is set out in the International Union of Railways "Leaflet 650 - Standard designation of axle arrangement on locomotives and multiple-unit sets". It is used in much...
- 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...