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| Soviet locomotive class AA20 | |||||||||||||||||||||||||||||||||
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 А. Андреев (Andreyev), the only 4-14-4 locomotive ever built | |||||||||||||||||||||||||||||||||
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The AA20 was a one-off steam locomotive constructed by the Soviet Union.
The AA20 was a "4-14-4" (Russian notation: 2-7-2) locomotive (using the Whyte notation classification of steam locomotives by wheel arrangement). It featured four leading wheels, fourteen coupled driving wheels (seven axles) in a rigid frame, and four trailing wheels.[ citation needed ]
Equivalent classifications in other notations would have been:[ citation needed ]
By the 1930s On Soviet railways, the requirements for traction and train speed increased significantly. The existing steam locomotives of type 0-5-0 (series E) and type 1-5-0, the adhesion weight of which did not exceed 85 tons, were no longer able to fully cope with the increased volume of transportation. There was an urgent need to replace them with much more powerful locomotives.[ citation needed ]
Different groups of specialists proposed different solutions. Some suggested leaving five driving wheel pairs on the locomotive and only increasing the load from the axle on the rails, while strengthening the railway track. Others insisted on keeping the load from the driving wheel sets within 20 tons, while increasing their number. Both groups of specialists did not take into account that at that time the cars were mainly equipped with a screw harness ( automatic couplers on Soviet railways would be installed en masse only in 1934), which could withstand a force not exceeding 20 tf.[ citation needed ]
A significant motivating factor in the creation of the Soviet steam locomotive type 2-7-2 was the experience of German and mainly North American locomotive building, in the creation of steam locomotives with six moving axles in one rigid frame, respectively, types: 1-6-0 and 2- 6-1.[ citation needed ]
The technical assignment, issued in the spring of 1930, for an alternative preliminary design of a Soviet high-speed freight steam locomotive, with more than five moving axles in one rigid frame, provided for a maximum axial load on the rails of 20 tons, that is, the same as for the preliminary design of a Soviet steam locomotive type 1-5-1 (future FD), which significantly complicated the task for designers. If for the high-speed American type 2-6-1 with an average design axle load from the driving wheel pair on the rail - 26.9 tons - back in 1926, it was possible to successfully implement the specified traction and speed characteristics, then for the high-speed Soviet design version, taking into account given axial load - 20 tons, the number of driving axles had to be increased to seven... At the same time, inevitably, according to the conditions for ensuring fit into the curves, The design of the driving mechanism and crew part became even more complicated. However, the acquisition of practical experience in solving such a complex technical problem was considered appropriate for the young Soviet school of locomotive building, in terms of the implementation of an unusually large-sized locomotive boiler and crew part with seven coupling axles - an absolute record in the practice of world locomotive building.[ citation needed ]
In 1931, a group of young engineers, graduates of MIIT, prepared a preliminary design of a steam locomotive with a 1-7-2 wheel arrangement and a rail load not exceeding 20 t from the wheel pair. In theory, such a locomotive should have provided maximum carrying capacity and significantly reduced the cost of transportation due to the possibility of using low-grade coal and eliminating the use of articulated locomotives. At the same time, the load on the rails, which does not go beyond the standards, would allow the use of such locomotives without special reinforcement of the tracks. The driving wheels of the locomotive with a diameter of 1550 mm were located in one rigid frame.
Working drawings of the new locomotive were already drawn up at the Voroshilovgrad Locomotive Plant, which was given the task by the NKPS to manufacture two locomotives of this type. However, during the detailed design it turned out that when using the 1-7-2 wheel formula it would not be possible to withstand the weight restrictions, so it was decided to switch to the 2-7-2 type. In addition to changing the wheel formula, the project has undergone a number of other changes. In particular, the diameter of the cylinders was increased from 735 to 740 mm, and the area of the grate was increased from 10 m2 to 12 m2. The steam pressure in the boiler should have been 17 kgf/cm2. The locomotive received a radial boiler firebox, a timber frame and a steam superheater of the Chusov system. The production of the locomotive at the plant proceeded slowly, largely due to the fact that at the same time the plant was mastering the mass production of FD type 1-5-1 steam locomotives. For the same reasons, it was decided to abandon the production of a second locomotive. The locomotive was ready only at the end of 1934. The new locomotive received the letter designation AA (in honor of Andrei Andreevich Andreev, who held the post of People's Commissar of the NKPS in 1931-1935) and the full designation of the locomotive AA20-1 (20 is the load from the moving wheelsets on the rails in tons).
The locomotive's weight was 140 tons, the cylinder diameter was 735 mm, and the piston stroke was 812 mm. The area of the grate was 10 m2, and the evaporating heating surface of the boiler was 445 m2. Much of the calculation work on the crew section was carried out by engineer K.P. Korolev, a future major specialist in the field of locomotive dynamics, the author of many books.
A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material to heat water in the locomotive's boiler to the point where it becomes gaseous and its volume increases 1,700 times. Functionally, it is a steam engine on wheels.
A tank locomotive or tank engine is a steam locomotive which carries its water in one or more on-board water tanks, instead of a more traditional tender. Most tank engines also have bunkers to hold fuel; in a tender-tank locomotive a tender holds some or all of the fuel, and may hold some water also.
The Whyte notation is a classification method for steam locomotives, and some internal combustion locomotives and electric locomotives, by wheel arrangement. It was devised by Frederick Methvan Whyte, and came into use in the early twentieth century following a December 1900 editorial in American Engineer and Railroad Journal.
Under the Whyte notation for the classification of steam locomotives, a 2-10-4 locomotive has two leading wheels on one axle, usually in a Bissel truck, ten coupled driving wheels on five axles, and four trailing wheels on two axles, usually in a bogie. These were referred to as the Texas type in most of the United States, the Colorado type on the Burlington Route, and the Selkirk type in Canada.
Under the Whyte notation for the classification of steam locomotives, 4-8-4 represents the wheel arrangement of four leading wheels on two axles, eight powered and coupled driving wheels on four axles and four trailing wheels on two axles. The type was first used by the Northern Pacific Railway, and initially named the Northern Pacific, but railfans and railroad employees have shortened the name since its introduction. It is most-commonly known as a Northern.
Under the Whyte notation for the classification of steam locomotives, 2-10-0 represents the wheel arrangement of two leading wheels on one axle, ten powered and coupled driving wheels on five axles, and no trailing wheels. This arrangement was often named Decapod, especially in the United States, although this name was sometimes applied to locomotives of 0-10-0 "Ten-Coupled" arrangement, particularly in the United Kingdom. Notable German locomotives of this type include the war locomotives of Class 52.
Lima Locomotive Works was an American firm that manufactured railroad locomotives from the 1870s through the 1950s. The company took the most distinctive part of its name from its main shop's location in Lima, Ohio. The shops were located between the Erie Railroad main line, the Baltimore & Ohio's Cincinnati-Toledo main line and the Nickel Plate Road main line and shops.
Under the Whyte notation for the classification of steam locomotives, 4-2-0 represents the wheel arrangement of four leading wheels on two axles, two powered driving wheels on one axle and no trailing wheels. This type of locomotive is often called a Jervis type, the name of the original designer.
Under the Whyte notation, a 2-8-4 is a steam locomotive that has two unpowered leading wheels, followed by eight coupled and powered driving wheels, and four trailing wheels. This locomotive type is most often referred to as a Berkshire, though the Chesapeake and Ohio Railway used the name Kanawha for their 2-8-4s. In Europe, this wheel arrangement was mostly seen in mainline passenger express locomotives and, in certain countries, in tank locomotives.
Under the Whyte notation for the classification of steam locomotives, 4-2-2 represents the wheel arrangement of four leading wheels on two axles, two powered driving wheels on one axle, and two trailing wheels on one axle.
On a steam locomotive, a trailing wheel or trailing axle is generally an unpowered wheel or axle (wheelset) located behind the driving wheels. The axle of the trailing wheels is usually located in a trailing truck. On some large locomotives, a booster engine was mounted on the trailing truck to provide extra tractive effort when starting a heavy train and at low speeds on gradients.
The Union Pacific Railroad 9000 Class was a class of 88 steam locomotives, built by ALCO for the Union Pacific between 1926 and 1930.
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.
Under the Whyte notation for the classification of steam locomotives by wheel arrangement, a 4-6-2+2-6-4 is a Garratt or Union Garratt articulated locomotive using a pair of 4-6-2 engine units back to back, with the boiler and cab suspended between them. The 4-6-2 wheel arrangement of each engine unit has four leading wheels on two axles, usually in a leading bogie, six powered and coupled driving wheels on three axles, and two trailing wheels on one axle, usually in a trailing truck.
London and North Western Railway (LNWR) 2-2-2 No. 3020 Cornwall is a preserved steam locomotive. She was built as a 4-2-2 at Crewe Works in 1847, but was extensively rebuilt and converted into her current form in 1858.
The South African Railways Class 21 2-10-4 of 1937 was a class of steam locomotives used in South Africa.
The leading wheel or leading axle or pilot wheel 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 on a leading truck. Leading wheels are used to help the locomotive negotiate curves and to support the front portion of the boiler.
The Russian locomotive class U was a Russian express passenger steam locomotive type. The class U was a 4-6-0 four-cylinder compound locomotive which used de Glehn compound system.
The Soviet locomotive class P36 was a Soviet mainline passenger steam locomotive type. Between 1950 and 1956, 251 locomotives were built. The locomotives were nicknamed "Generals" because of the red stripe down the side. The P36 had the same power as a class IS locomotive but the axle loading of 18 tons allowed its use on the vast majority of Russian railway lines, replacing class Su 2-6-2s and significantly increasing the weight of passenger trains. The P36 was the last type of mainline steam locomotive built in the Russian SFSR and the last one built, P36-0251, was the last steam locomotive produced by Kolomna Works, Russian SFSR. Though sometimes described as the "Victory" type locomotive, that nick-name actually belongs to the class L 2-10-0 built between 1945 and 1947.
Rigid-framed electric locomotives were some of the first generations of electric locomotive design. When these began the traction motors of these early locomotives, particularly with AC motors, were too large and heavy to be mounted directly to the axles and so were carried on the frame. One of the initial simplest wheel arrangements for a mainline electric locomotive, from around 1900, was the 1′C1′ arrangement, in UIC classification.