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| Soviet locomotive class AA20 | |||||||||||||||||||||||||||||||||||
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 А. Андреев , 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.
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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 ]
| | This section needs additional citations for verification .(July 2024) |
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 (series Ye), 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. [2]
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. [2]
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 (which would later become the class 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. [2]
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.
The AA steam locomotive was the first and only locomotive in the world history with seven driving axles in one rigid frame. The steam locomotive's boiler was one of the largest locomotive boilers in Europe. Due to the sheer size of the locomotive, a number of measures were taken to improve the curve fit of the locomotive. In particular, the front bogie was able to deviate from the longitudinal axis of the locomotive within ± 145 mm (at the extreme points), the rear bogie - within ± 265 mm. The clearance of the first and second wheelsets was ± 27 mm, the seventh ± 35 mm. In addition, the wheels of the third, fourth and fifth pairs had no ridges, and the width of their bands was 175 mm.
The locomotive was also distinguished by an original system of force transmission from the steam engine piston rod to the driving wheelsets. Thus, on a conventional steam locomotive the tractive force is transmitted to one of the axles (leading wheelset), and from it through drawbars directly to all other moving axles. On the AA locomotive the tractive force was transmitted to the fourth driving axle, and from it the tractive force was directly transmitted to the first three coupling axles. This axle was also connected to the fifth wheelset by a special drawbar, and the sixth and seventh axles were driven directly from the fifth driving axle.
A bogie is a chassis or framework that carries a wheelset, attached to a vehicle—a modular subassembly of wheels and axles. Bogies take various forms in various modes of transport. A bogie may remain normally attached or be quickly detachable. It may include a suspension component within it, or be solid and in turn be suspended ; it may be mounted on a swivel, as traditionally on a railway carriage or locomotive, additionally jointed and sprung, or held in place by other means.
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 Climax locomotive is a type of geared steam locomotive built by the Climax Manufacturing Company, of Corry, Pennsylvania. These had two steam cylinders attached to a transmission located under the center of the boiler, which sent power to driveshafts running to the front and rear trucks. Some 1,000-1,100 were built in three classes between 1888 and 1928.
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.
Orenstein & Koppel was a major German engineering company specialising in railway vehicles, escalators, and heavy equipment. It was founded on April 1, 1876, in Berlin by Benno Orenstein and Arthur Koppel.
Main components found on a typical steam locomotive include:
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.
Under the Whyte notation for the classification of steam locomotives, 4-2-4 represents the wheel arrangement of four leading wheels on two axles, two powered driving wheels on one axle, and four trailing wheels on two axles.
The Union Pacific Railroad 9000 Class was a class of 88 steam locomotives, built by ALCO for the Union Pacific between 1926 and 1930.
An adhesion railway relies on adhesion traction to move the train, and is the most widespread and common type of railway in the world. Adhesion traction is the friction between the drive wheels and the steel rail. Since the vast majority of railways are adhesion railways, the term adhesion railway is used only when it is necessary to distinguish adhesion railways from railways moved by other means, such as by a stationary engine pulling on a cable attached to the cars or by a pinion meshing with a rack.
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.
A 2-4-6-2 steam locomotive, in the Whyte notation for describing locomotive wheel arrangements, has a two-wheel leading truck, one set of four driving wheels, one set of six driving wheels, and a two-wheel trailing truck.
The South African Railways Class 5 4-6-2 of 1912 was a steam locomotive.
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.