B-B and Bo-Bo are the Association of American Railroads (AAR) and British classifications of wheel arrangement for railway locomotives with four axles in two individual bogies . They are equivalent to the B′B′ and Bo′Bo′ classifications in the UIC system. The arrangement of two, two-axled, bogies is a common wheel arrangement for modern electric and diesel locomotives .
20-541: The Class ED79 ( ED79形 ) was a Bo-Bo wheel arrangement AC electric locomotive type operated on passenger and freight services in the north of Japan from 1986, originally by Japanese National Railways (JNR), and later by Hokkaido Railway Company (JR Hokkaido) and Japan Freight Railway Company (JR Freight) until 2016. 21 Class ED79-0 locomotives were converted between 1986 and 1987 at JNR 's Omiya, Tsuchizaki, and Naebo Workshops from former Class ED75-700 locomotives to haul both freight and passenger trains through
40-692: A Bo-Bo is regarded as a B-B because the AAR system does not take traction motors into consideration, only powered axles. An AAR-like notation is used in France too, making it hard to tell the B-B and Bo-Bo engines apart, both of which are common there. Railcars and multiple units use similar two-axle powered bogies and many of them use similar hydraulic or mechanical transmissions, rather than traction motors. However railcars are also lightweight and do not require all axles to be powered in order to gain adequate adhesion. They thus use
60-509: A wheel arrangement of 1A-A1 or A1-1A rather than B-B. A common arrangement is for each power car to have two independent engines and transmissions, each driving a single axle of each bogie. The difference between 1A-A1 and A1-1A is that 1A-A1 has the powered axles closest to the middle of the car, whilst A1-1A has the powered axles closest to the ends. The 2'Bo' (AAR:2-B) arrangement has been used similarly, but rarely, for lightweight railcars that only needed two powered axles. Only one example
80-415: Is recorded, the diesel-electric four-car Rebel railcars of 1935. Three powercars were built, with a 600 bhp engine and two traction motors on a single bogie. Half of the powercar was used as a baggage car, supported by a conventional coaching stock unpowered bogie. UIC classification of locomotive axle arrangements The UIC classification of locomotive axle arrangements , sometimes known as
100-565: Is the UIC indication of a wheel arrangement for railway vehicles with four axles in two individual bogies , all driven by their own traction motors . It is a common wheel arrangement for modern electric and diesel-electric locomotives , as well as power cars in electric multiple units . Most early electric locomotives shared commonalities with the steam engines of their time. These features included side rods and frame mounted driving axles with leading and trailing axles. The long rigid wheelbase and
120-454: Is then transmitted to the bogies by cardan shafts and a short driveshaft between axles. A common example of this is the German V200 design and its many international derivatives. The need to arrange the bogie suspension around the drive shafts led to an unusual bogie design with radius arms rather than hornblocks and so prominently visible wheels and rims. In some rare examples, such as
140-534: The China Railways HXD2 and the Indian WAG-12 . The B′B′ or B-B arrangement is similar, but usually applies to diesel-hydraulic locomotives rather than diesel-electrics. The axles on each bogie are coupled together mechanically, rather than being driven by individual traction motors. Diesel-hydraulics have their engine mounted on the main frame of the locomotive, together with a hydraulic transmission. Power
160-542: The ED76 and ED78 . These used flexicoil outer bogies which permitted the bogies some lateral movement, as well as swivelling. These are a pair of Bo′Bo′ locomotives semi-permanently coupled as a single unit. They are each constructed with a single cab, giving a cab at each end. This layout includes the Alstom Prima II , one of the most powerful electric locomotives in production (9 MW (12,000 hp)). Versions include
180-751: The German classification or German system , describes the wheel arrangement of locomotives , multiple units and trams . It is used in much of the world, notable exceptions being the United Kingdom and North America . The classification system is managed by the International Union of Railways (UIC). The UIC uses the following structure: Garratt locomotives are indicated by bracketing or placing plus signs between all individual units. The most common wheel arrangements in modern locomotives are Bo′Bo′ and Co′Co′. The following examples are based on
200-469: The SNCF Class BB 71000 and the narrow-gauge ÖBB 2095 [ de ] , the bogie axles have been linked by coupling rods . Having only a single final-drive per bogie allows more room for the bogie pivots on this narrow-gauge design. With high power full-size locomotives, splitting the drive directly to two axles is preferred, as it only requires a less powerful final drive gearbox. In AAR notation
220-469: The ED79-0 subclass, these were intended to haul freight and passenger trains through the undersea Seikan Tunnel between Honshu and Hokkaido, but as a cost-saving measure, only one cab end was equipped with the necessary ATC equipment, so these locomotives were only able to operate in multiple with an ED79-0 locomotive and were not permitted to run singly through the tunnel. An ED79-100 locomotive would be coupled at
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#1733084570996240-705: The Japanese 3 ft 6 in ( 1,067 mm ) narrow-gauge Bo-Bo electric JNR Class ED61 [ ja ] were rebuilt in the late 1970s to form the Class ED62 . An additional carrying axle was added between the bogies to give a B-1-B (AAR) or Bo′1Bo′ (UIC) arrangement. The intention was to give a lighter axle loading for the Iida Line . Another rare arrangement was the Bo-2-Bo used for two 3 ft 6 in ( 1,067 mm ) gauge Japanese electric classes,
260-539: The Seikan Tunnel. All were scheduled to be withdrawn by March 2016 when the line voltage through the Seikan Tunnel was raised from 20 kV AC to 25 kV AC with the opening of the Hokkaido Shinkansen . The withdrawal dates for the fleet are shown below. 13 Class ED79-100 locomotives were converted between 1986 and 1987 at JNR 's Omiya, Tsuchizaki, and Naebo Workshops from former Class ED75-700 locomotives. As with
280-409: The Seikan Tunnel. These locos were finished from new in the then-new JR Freight livery of pale purple and two-tone blue, with maroon ("Red No. 2") cab doors. As of March 2015, nine out of the original ten Class ED79-50 locomotives remained in service, owned by JR Freight and based at Goryokaku Depot. These were normally used in pairs to haul freight services between Higashi-Aomori and Goryokaku via
300-409: The advent of modern motors and electronics more power can be brought to the rail with only a few axles. Modern electric locomotives can deliver up to 6400 kW on only four axles. For very heavy loads, especially in transportation of bulk goods, a single unit with this wheel arrangement tends to have too little adhesive weight to accelerate the train sufficiently fast without wheelslip . Eighteen of
320-747: The increased availability of Class EH500 locomotives. By 1 April 2013, nine Class ED79-0 locomotives remained in service, owned by JR Hokkaido and based at Hakodate Depot. These were used to haul the Cassiopeia , Hokutosei , Twilight Express , and Hamanasu overnight services between Aomori and Hakodate via the Seikan Tunnel. All remaining locomotives had been withdrawn by March 2016. The fleet details are shown below. From February 2000, eight locomotives (numbers 3, 8, 10, 11, 14, 17, 19, and 21) received differing Doraemon liveries. 10 Class ED79-50 locomotives were built between 1989 and 1990 by Toshiba for JR Freight for use on freight services through
340-421: The leading and trailing axles reduced cornering stability and increased weight. The Bo-Bo configuration allowed for higher cornering speeds due to the smaller rigid wheelbase. Furthermore, it allowed better adhesion because all the wheels were now powered. Due to the absence of frame mounted wheels no leading or trailing axles were necessary to aid cornering, reducing weight and maintenance requirements. Due to
360-475: The northern end of an ED75-0. With the privatization of JNR on 1 April 1987, all 13 locomotives were transferred to the ownership of JR Hokkaido, although they were also loaned for use on JR Freight services until 2006. The last remaining member of the sub-class was withdrawn in March 2009. The fleet details are shown below. The ED79 classification for this locomotive type is explained below. Bo-Bo Bo-Bo
380-570: The ownership of JR Hokkaido . Daytime Kaikyo services previously hauled by Class ED79 locomotives between Aomori and Hakodate through the Seikan Tunnel were discontinued in 2002, replaced by the Hakucho and Super Hakucho limited express services using electric multiple unit (EMU) trains). In 2006, the Nihonkai sleeping car service no longer ran through the tunnel, and JR Freight also ceased using JR Hokkaido locomotives on freight services, due to
400-407: The undersea Seikan Tunnel between the main island of Honshu and the northern island of Hokkaido , which opened in March 1988. The gear ratio was reduced from the 4.44 of the original ED75 locomotives to 3.38, giving a top speed of 110 km/h (70 mph) better suited to express passenger and freight workings. With the privatization of JNR on 1 April 1987, all 21 locomotives were transferred to
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