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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.
The 4-2-0 wheel arrangement type was common on United States railroads from the 1830s through the 1850s. The first 4-2-0 to be built was the Experiment, later named Brother Jonathan, for the Mohawk and Hudson Railroad in 1832. It was built by the West Point Foundry based on a design by John B. Jervis. Having little else to reference, the manufacturers patterned the boiler and valve gear after locomotives built by Robert Stephenson of England. A few examples of Stephenson locomotives were already in operation in America, so engineers did not have to travel too far to get their initial ideas.
In England, the 4-2-0 was developed around 1840 from the 2-2-2 design of Stephenson's first Long Boiler locomotive, which he had altered to place two pairs of wheels at the front to improve stability, with the outside cylinders between them.
In the United States, the design was a modification of the 0-4-0 design, then in common use. The 0-4-0 proved to be too rigid for the railroads of the day, often derailing on the tight curves and rapid elevation changes of early American railroads. For the 4-2-0, Jervis introduced a four-wheel leading truck under the locomotive's smokebox. It swiveled independently from the main frame of the locomotive, in contrast to the English 4-2-0 engines which had rigid frames. The pistons powered a single driving axle at the rear of the locomotive, just behind the firebox. This design resulted in a much more stable locomotive which was able to guide itself into curves more easily than the 0-4-0. [1] [2]
This design proved so effective on American railroads that many of the early 0-4-0s were rebuilt as 4-2-0s. The 4-2-0 excelled in its ability to stay on the track, especially those with the single driving axles behind the firebox, whose main virtue was stability. However, with only one driving axle behind the firebox, the locomotive's weight was spread over a small proportion of powered wheels, which substantially reduced its adhesive weight. On 4-2-0 locomotives which had the driving axle in front of the firebox, adhesive weight was increased. While this plan placed more of the locomotive's weight on the driving axle, it reduced the weight on the leading truck which made it more prone to derailments. [1] [2]
One possible solution was patented in 1834 by E.L. Miller and used extensively by Matthias W. Baldwin. It worked by raising a pair of levers to attach the tender frame to an extension of the engine frame, which transferred some weight from the tender to the locomotive frame and increased the adhesive weight. An automatic version was patented in 1835 by George E. Sellers and was used extensively by locomotive builder William Norris after he obtained rights to it. This system used a beam whose fulcrum was the driving axle. On flat and level surfaces, the beam would be slightly raised, but upon starting or on grades, the resistance made the beam assume a horizontal position which caused the locomotive to tip upward. [1] [2]
A more practical solution, first put into production by Norris, relocated the driving axle to a location on the frame in front of the locomotive's firebox. This was done because Baldwin refused to grant rights to Norris to use his patented "half-crank" arrangement. Cantilevering the weight of the firebox and the locomotive crew behind the driving axle placed more weight on the driving axle without substantially reducing the weight on the leading truck. However, Norris's design led to a shorter wheelbase, which tended to offset any gains in tractive force on the driving axle by reducing the locomotive's overall stability. A number of Norris locomotives were imported into England for use on the Birmingham and Bristol Railway since, because of the challenges presented by the Lickey Incline, British manufacturers declined to supply. [1] [2]
Once steel became available, greater rotational speeds became possible with multiple smaller coupled wheels. Five years after new locomotive construction had begun at the West Point Foundry in the United States with the 0-4-0 Best Friend of Charleston in 1831, the first 4-4-0 locomotive was designed by Henry R. Campbell, at the time the chief engineer for the Philadelphia, Germantown and Norristown Railway. Campbell received a patent for the design in February 1836 and soon set to work building the first 4-4-0. For the time, Campbell's 4-4-0 was a giant among locomotives. Its cylinders had a 14 inches (356 millimetres) bore with a 16 inches (406 millimetres) piston stroke, it boasted 54 inches (1,372 millimetres) diameter driving wheels, could maintain 90 pounds per square inch (620 kilopascals) of steam pressure and weighed 12 short tons (10.9 tonnes). Campbell's locomotive was estimated to be able to pull a train of 450 short tons (410 tonnes) at 15 miles per hour (24 kilometres per hour) on level track, outperforming the strongest of Baldwin's 4-2-0s in tractive effort by about 63%. However, the frame and driving gear of his locomotive proved to be too rigid for the railroads of the time, which caused Campbell's prototype to be derailment-prone. [1] [2]
As the 1840s approached and more American railroads began to experiment with the new 4-4-0 locomotive type, the 4-2-0 fell out of favor since it was not as able as the 4-4-0 to pull a paying load. 4-2-0s continued to be built into the 1850s, but their use was restricted to light-duty trains since, by this time, most railroads had found them unsuitable for regular work. [1] [2]
In England, for freight work, four-coupled and six-coupled engines were performing well. However, for passenger work the aim was greater speed. Because of the fragility of cast-iron connecting rods, "singles" continued to be used, with the largest driving wheels possible.
For some reason, British manufacturers did not take up the idea of mounting the forward wheels on a bogie for some years. There were possibly fears about their stability and with a long rigid frame, greater speed was achieved, albeit at the cost of a very rough ride and damage to the track. The culmination of this approach was seen in the Crampton locomotive where, to make the driving wheels as large as possible, they were mounted behind the firebox. [1] [2] [3]
In 1923, the South African Railways conducted trials with a prototype petrol-paraffin powered road-rail tractor and, in 1924, placed at least two Dutton steam road-rail tractors in service on the new 2 ft (610 mm) narrow gauge line between Naboomspruit and Singlewood in Transvaal. The petrol-paraffin prototype and one of the latter had a 4-2-0 wheel arrangement. [4] [5]
The prototype was a modified Dennis tractor which was fitted with a removable bogie between the front wheels to lift them high enough to prevent ground contact. A ball pin on the bogie fit into a socket in the front axle, and the bogie could easily be removed or replaced by running the tractor up a pair of ramps, placed on both sides of the track. [4] [6] [7] [8]
The production model was a modified Yorkshire steam tractor, fitted with jacks at the front to allow a separate bogie to be manoeuvred into position underneath the front axle to guide it on the rails. Without the bogie, the vehicle could still be driven on ordinary roads and had the advantage of being able to be detached and run around the train, without requiring special loops for that purpose. For reversing on the track, as when shunting, the rear wheels were modified to be steerable. [5] [9]
The first railroad locomotive to operate in Chicago, Illinois was a 4-2-0, the Pioneer , which was built in 1837 by Baldwin Locomotive Works for the Utica and Schenectady Railroad in New York. It was later purchased used by William B. Ogden for the Galena and Chicago Union Railroad, the oldest predecessor of the Chicago and North Western Railway. The locomotive arrived in Chicago by schooner on 10 October 1848 and it pulled the first westbound train out of the city fifteen days later, on 25 October 1848. [10]
Mason Bogie locomotives are a type of articulated steam locomotive suited for sharp curves and uneven track, once commonly used on narrow gauge railways in the United States of America. The design is a development of the Single Fairlie locomotive.
A Fairlie is a type of articulated steam locomotive that has the driving wheels on bogies. The locomotive may be double-ended or single ended. Fairlies are most associated with the Ffestiniog Railway in Wales.
A tank locomotive or tank engine is a steam locomotive that 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.
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.
This is a glossary of the components found on typical steam locomotives.
Under the Whyte notation for the classification of steam locomotives by wheel arrangement, 4-6-0 represents the configuration of four leading wheels on two axles in a leading bogie and six powered and coupled driving wheels on three axles with the absence of trailing wheels. In the mid 19th century, this wheel arrangement became the second most popular configuration for new steam locomotives in the United States, where this type is commonly referred to as a ten-wheeler. As a locomotive pulling trains of lightweight all-wood passenger cars in the 1890–1920s, it was exceptionally stable at near 100 mph (160 km/h) speeds on the New York Central's New York to Chicago Water Level Route and on the Reading Railroad's Camden to Atlantic City, NJ, line. As passenger equipment grew heavier with all steel construction, heavier locomotives replaced the ten-wheeler.
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. This type of locomotive is often called a Huntington type.
A Meyer locomotive is a type of articulated locomotive. The design was never as popular as the Garratt or Mallet locomotives. It can be best regarded as 19th Century competition for the early compound Mallet and also the Fairlie articulated designs. Most single cab modern trains are of a similar design such as power cars, freight diesel locomotives, and some passenger locomotives.
A jackshaft is an intermediate shaft used to transfer power from a powered shaft such as the output shaft of an engine or motor to driven shafts such as the drive axles of a locomotive. As applied to railroad locomotives in the 19th and 20th centuries, jackshafts were typically in line with the drive axles of locomotives and connected to them by side rods. In general, each drive axle on a locomotive is free to move about one inch (2.5 cm) vertically relative to the frame, with the locomotive weight carried on springs. This means that if the engine, motor or transmission is rigidly attached to the locomotive frame, it cannot be rigidly connected to the axle. This problem can be solved by mounting the jackshaft on unsprung bearings and using side-rods or chain drives.
A lateral motion device is a mechanism used in some railroad locomotives which permits the axles to move sideways relative to the frame. The device facilitates cornering.
London & North Western Railway 2-2-2 No. 3020 Cornwall is a preserved steam locomotive. She was built at Crewe in 1847. She was originally a 4-2-2 in 1847, but was extensively rebuilt, and converted to a 2-2-2 in 1858.
A Bissell or Bissel truck is a single-axle bogie which pivots towards the centre of a steam locomotive to enable it to negotiate curves more easily. Invented in 1857 by Levi Bissell and usually then known as a pony truck, it is a very simple and common means of designing a carrying wheel.
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.
A duplex locomotive is a steam locomotive that divides the driving force on its wheels by using two pairs of cylinders rigidly mounted to a single locomotive frame; it is not an articulated locomotive. The concept was first used in France in 1863, but was particularly developed in the early 1930s by the Baldwin Locomotive Works, the largest commercial builder of steam locomotives in North America, under the supervision of its then chief engineer, Ralph P. Johnson.
A divided drive locomotive is a steam locomotive that divides the driving force on its wheels by using different cylinders to power different pairs of driving wheels in order to give better weight distribution and reduce "hammer blow" which can be damaging to the track, or else to enable the wider spacing of the driving wheels to accommodate a larger firebox.
The South African Railways Dutton road-rail tractors of 1923 were road-rail steam tractors.
Henry Roe Campbell was an American surveyor and civil engineer. Campbell contributed to American railroading and bridge-building in the first half of the 19th century. Campbell patented his 4-4-0 design in February 1836, just a few months before the patent law was changed to require that claims include proof of originality or novelty.
Under the Whyte notation for the classification of steam locomotives, 0-6-6 represents the wheel arrangement of no leading wheels, six powered and coupled driving wheels on three axles and six trailing wheels on three axles.
A cannon bearing or cannon box bearing is an arrangement of bearings on a shaft, usually an axle, where two bearings are mounted in an enclosed tube.
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