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La disposición de rueda de AAR sistema es un método de clasificación de la locomotora (o unidad) arreglos de la rueda que fue desarrollado por la Asociación Americana de Ferrocarriles . Es esencialmente una simplificación de la clasificación europea UIC , y se usa ampliamente en América del Norte para describir locomotoras diesel y eléctricas (incluidas las locomotoras eléctricas de tercer carril). No se usa para locomotoras de vapor que usan la notación Whyte en su lugar.
El sistema AAR cuenta los ejes en lugar de las ruedas. Las letras se refieren a ejes motorizados y los números a ejes no motorizados (o intermedios). "A" se refiere a un eje motorizado, "B" a dos ejes motorizados en una fila, "C" a tres ejes motorizados en una fila y "D" a cuatro ejes motorizados en una fila. "1" se refiere a un eje loco y "2" a dos ejes libres en una fila. Un guión ("-") separa los camiones o conjuntos de ruedas. Un signo más ("+") se refiere a la articulación, ya sea conectando bogies con soportes de tramo o conectando locomotoras individuales a través de barras de tracción sólidas en lugar de acopladores .
1A-A1 [ editar ]
"1A-A1" significa que hay dos carretillas (o conjuntos de ruedas) debajo de la unidad. Cada camión tiene un eje motorizado y un eje intermedio, con los ejes intermedios hacia el exterior. Los ejemplos incluyen automóviles Budd RDC Diesel MU ( DMU ).
1B-1B [ editar ]
"1B-1B" significa que hay dos camiones con un eje intermedio delantero delante de dos ejes motorizados. Este arreglo se utilizó para actualizar el arreglo BB de dos locomotoras BB EMC 1800 hp propiedad del Ferrocarril de Santa Fe en 1938, para una mayor estabilidad a la velocidad.
1-D [ editar ]
"1-D" significa que hay dos camiones o grupos de ejes; el camión "1" está debajo de la parte delantera de la unidad y tiene un eje loco. Los 4 ejes restantes están montados rígidamente al bastidor detrás de este camión principal (o agrupados en un segundo camión). Esto es aproximadamente el equivalente a una consolidación 2-8-0 en la notación Whyte, particularmente cuando se construye como una locomotora de 1 camión / 4 ejes rígidos. Los únicos ejemplos conocidos son una serie de locomotoras diésel de cabina cerrada construidas y propiedad del Ferrocarril Mexicano de Texas . [1]
2-A1A [ editar ]
"2-A1A" significa que hay dos carretillas o conjuntos de ruedas. El camión "2" está debajo de la parte delantera de la unidad y tiene dos ejes tensores en una fila. El camión "A1A" está debajo de la parte trasera de la unidad y tiene un eje motor, un eje loco y un eje motor más. Un ejemplo es el vagón FM OP800 de 800 hp (600 kW), seis de los cuales fueron construidos por la St. Louis Car Company exclusivamente para el ferrocarril del sur en 1939.
2-B [ editar ]
"2-B" significa que hay dos camiones o conjuntos de ruedas. El camión "2" está debajo de la parte delantera de la unidad y tiene dos ejes tensores en una fila. El camión "B" está debajo de la parte trasera de la unidad y tiene dos ejes motorizados. Los ejemplos incluyen los tres coches eléctricos ligeros construidos por ALCO / ACF en 1935 y 1937 para su uso con los aerodinámicos Rebel .
3-A1A [ editar ]
"3-A1A" significa que hay dos carretillas o conjuntos de ruedas. El camión "3" está debajo de la parte delantera de la unidad y tiene tres ejes tensores en una fila. El camión "A1A" está debajo de la parte trasera de la unidad y tiene un eje motor, un eje loco y un eje motor más. Un ejemplo es el vagón FM OP800 de 800 hp (600 kW) construido más tarde , seis de los cuales fueron construidos por St. Louis Car Company exclusivamente para el ferrocarril del sur en 1939.
A1-1A [ editar ]
"A1-1A" significa que hay dos carretillas o conjuntos de ruedas debajo de la unidad. Cada camión tiene un eje motorizado y un eje loco, con los ejes motorizados hacia el exterior.
A1A-2 [ editar ]
"A1A-2" significa que hay dos camiones. El camión "A1A" está debajo de la parte delantera de la unidad y tiene un eje motor, un eje loco y un eje motor más. El camión "2" está debajo de la parte trasera de la unidad y tiene dos ejes libres en una fila. Un ejemplo es el coche eléctrico Silver Charger del General Pershing Zephyr .
A1A-3 [ editar ]
"A1A-3" significa que hay dos camiones. El camión "A1A" está debajo de la parte delantera de la unidad y tiene un eje motor, un eje loco y un eje motor más. El camión "3" está debajo de la parte trasera de la unidad y tiene tres ejes libres en una fila. Un ejemplo es la unidad de cabina Baldwin DR-6-2-10 de 1000 hp (750 kW), de la cual solo una se construyó para Chicago y North Western Railway en 1948.
A1A-A1A [ editar ]
"A1A-A1A" means there are two trucks under the unit. Each truck has two powered axles, with an idler axle between them. This spreads the weight of the locomotive more evenly over the track and counteracts the tendency of trucks to oscillate at high speeds, which is a problem with two axle trucks. The idler wheels may be smaller than the powered wheels.
Examples include the EMD E-units and ALCO PAs, which were high speed passenger locomotives, and the dual service FM Erie-built. BNSF took delivery of ES44C4 locomotives with this type of truck in 2009. In the UK the class 31.
A1A-B+B[edit]
"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 bolster under the rear of the unit. The only example to date of this arrangement was a single experimental EMD SDP45.
B[edit]
"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 40. This arrangement is sometimes referred to as 0-4-0, the Whyte notation equivalent.
B-1[edit]
"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 LWT12 locomotives built by EMD in 1956.
B-2[edit]
"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-210 locomotives built by Baldwin in 1956 and 1957 for use with Pullman-Standard Train-X equipment.
B-A1A[edit]
"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-liners (most passenger units) built from 1950 to 1955, and the EMD FL9.
B-B[edit]
"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 and high-speed rail, as well as in switching. Examples include the EMD GP (General Purpose), EMD F-units, EMD SW1500, Acela Express Power Cars, Siemens Charger, Siemens ACS-64 and GE Genesis units. High speed ("time") freight trains, with guaranteed schedules often use B-B locomotives of 3,800 HP (950 HP per axle), but this application, too, has largely been replaced by higher-powered, 4,500 HP C-C locomotives (750 HP per axle). An American Colloquialism of "B-B" is "Four axle".
B-2-B[edit]
"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.
B-B-B[edit]
"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. The EMD GM10B was a notable example. See also Bo-Bo-Bo.
B+B+B[edit]
"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 Railway GE boxcab electrics of 1923 are examples of this wheel arrangement.
2-B+B-2[edit]
"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 DD1 and DD2 electric locomotives used this arrangement.
2-B+B+B+B-2[edit]
"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-1 "Boxcab" electrics.
B+B-B+B[edit]
"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 bolsters. One example would be the General Electric U50, built from 1963 to 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 4,000 hp (3,000 kW) locomotive with a B+B-B+B wheel arrangement.
B-B+B-B[edit]
"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 bolster. In most cases, the locomotive is articulated over the span bolster. The Union Pacific's M-10002 diesel streamliner and New York Central's T-Motor third rail electric locomotives are examples 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.
B-B-B-B[edit]
"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[edit]
"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[edit]
"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 (e.g. the PRR B1). This arrangement is sometimes referred to as 0-6-0, the Whyte notation equivalent.
C-B[edit]
"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.
C-C[edit]
"C-C" means there are two identical trucks. Each truck has three powered axles. Examples include the EMD SD (Special Duty), GMD GF6C, EMD GM6C, PRR E44, GE E60, Virginian EL-C and GE Evolution Series units, except the ES44C4 and ET44C4 which use the A1A-A1A wheel arrangement. This is a currently popular configuration used in low-speed, high-weight applications, such as unit coal trains. General ("manifest") freight trains also use C-C locomotives. See also Co-Co. An American colloquialism of "C-C" is "Six axle".
1-C+C-1[edit]
"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 FF1 and FF2 electric locomotives used this arrangement.
2-C+C-2[edit]
"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 Pennsylvania Railroad's GG1 electric locomotives were notable examples of this arrangement.
2+C-C+2[edit]
"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[edit]
"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 coal-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.
C-C+C-C[edit]
"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 locomotives built by General Electric for Union Pacific. These locomotives consisted of two permanently coupled C-C units.
C+C-C+C[edit]
"C+C-C+C" means there are four trucks. Each truck has three powered axles and pairs of them are connected by span bolsters. 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.
1-D-1[edit]
"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 New York Central S-Motor third rail electric locomotives, for the Grand Central Terminal electrification and the Great Northern Z-1 electric locomotives for the Cascade Tunnel electrification, used this arrangement.
2-D-2[edit]
"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 PRR R1 electric locomotive used this arrangement.
D-D[edit]
"D-D" means there are two trucks. Each truck has four powered axles. Examples include the EMD DD units.
D-D locomotives so far have fallen out of favor as nearly all of these have been twin-engined locomotives, which placed too much horsepower in too few axles, thereby making these consists rather inflexible (each locomotive featured two prime movers, making each unit essentially a pair of high-powered B-B locomotives on a common frame as far as traction and power was concerned).
In fact, a usual consist of a D-D unit included a leading C-C unit and a trailing C-C unit, for a total of about 12,600 HP (with four total prime-movers).
With today's higher horsepower C-C units (about 4,300 HP apiece), three such C-C units exceeds the total power of the usual D-D consist by 300 HP (with one fewer prime-mover than a usual D-D consist, thereby significantly improving reliability and dramatically reducing maintenance).
Although at this time the term D-D is associated with twin-prime-mover locomotives of high power, this does not preclude the possibility of a D-D with a single prime mover of high power some time in the future, nor of the term being used to describe a two-truck electric locomotive. The EMD DDM45 is a narrow-gauge adaptation of the SD45, which required additional axles due to the use of smaller traction motors.
2-D+D-2[edit]
"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 Baldwin DR-12-8-1500/2 "Centipede" diesel locomotives and the GE "Little Joe" electric locomotives.
B-D+D-B[edit]
"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 W-1 class of electric locomotives built by General Electric for the Great Northern Railway used this arrangement.
1B+D+D+B1[edit]
"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" electric locomotives used by the Milwaukee Road used this arrangement.
(B+B-B+B)+(B+B-B+B)[edit]
"(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 Railway's EL-2B electric locomotives.
See also[edit]
- Locomotives by wheel arrangement
- Swiss locomotive and railcar classification
- UIC classification
- Wheel arrangement
- Whyte notation
- Bogie Truck
- Co-Co locomotives
References[edit]
- ^ Texas-Mexican 701A
- Pinkepank, Jerry A. (1973). The Second Diesel Spotter's Guide. Milwaukee, WI: Kalmbach Publishing. ISBN 0-89024-026-4.
