Multiplex locomotive

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A multiplex locomotive is a steam locomotive that divides the driving force on its wheels by using multiple pairs of cylinders to drive multiple driving wheel set groups. Such a locomotive will necessarily articulated if it has more than two sets of driving wheels. There were locomotive projects with three, four, five or six sets of drive wheels. However, these locomotives were never built, except for four triplex locomotives in the United States and one quadruplex locomotive in Belgium.

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The names of the subgroups of multiplex locomotives is derived from the number of drive wheel sets and is composed of the numeral prefix and the word locomotive. However, locomotive is often omitted if it can be inferred from the context.

Duplex locomotives

Pennsylvania Railroad class T1 duplex locomotive Pennsylvania RR streamlined locomotive T1.jpg
Pennsylvania Railroad class T1 duplex locomotive

The terms duplex locomotive and Divided drive locomotive are used to describe locomotives with two drive wheel sets mounted in a rigid frame. [1] [ self-published source ]

The concept of the duplex locomotive originated in the early development of the compound locomotive, in which the high-pressure cylinders worked on drive wheels or drive wheel sets that were not coupled to those on which the low-pressure cylinders worked. Later, the concept was used to limit the force in the connecting rods and the hammer blow, i.e. the dynamic forces of the steam engine drive acting on the rail. This concept was used most notably by the Baldwin Locomotive Works in North America in the early 1930s. The most successful duplex locomotive of this type was the Pennsylvania Railroad's T1 class.

Articulated locomotives with two drive wheel sets were typically of the Mallet, the Garratt or the Meyer type. These types are not normally considered to be duplex locomotives. [1]

Triplex locomotives

Erie Railroad Matt H. Shay 2-8-8-8-2 Erie Railroad - 2603 steam locomotive (Baldwin 2-8-8-8-2) (27197514215).jpg
Erie Railroad Matt H. Shay 2-8-8-8-2
The only 2-8-8-8-4 built for the Virginian Railway 28884.jpg
The only 2-8-8-8-4 built for the Virginian Railway

Triplex locomotives are locomotives with three drive wheel sets. The Baldwin Locomotive Works built three 2-8-8-8-2 triplex locomotives for the Erie Railroad and one 2-8-8-8-4 for the Virginian Railway. All the triplex locomotives built were of the Mallet type, but with an extra set of driving wheels under the tender. They could only be used as slow pushers because of the enormous tractive effort was too much for the car couplings to withstand and the boiler did not produce enough steam to operate the locomotives at higher speeds.

The triplex locomotives for the Erie Railroad were built between 1914 and 1915 and were given the classification of P-1. [2] They were not considered successful and scrapped till 1933. [3]

The triplex locomotive built for the Virginian Railway, as No. 700, in 1916 was given classification of XA. It was considered unsuccessful as well and was sent back to Baldwin Locomotive Works where it was taken apart in 1920 and converted into a 2-8-8-0 and a 2-8-2. [4]

Quadruplex locomotives

Quadruplex locomotives are locomotives with four drive wheel sets. There was a project by Baldwin Locomotive Works and one by Beyer, Peacock & Company for the United States, both of which were never realised. The only quadruplex locomotive built was the Belgian quadruplex SNCB 2096, which was not successful.

United States

This type of articulated locomotive was never built, although George R. Henderson was granted a patent for a such a locomotive in June 1914, [5] which was assigned to the Baldwin Locomotive Company. The company presented the design to the Atchison, Topeka, & Santa Fe Railway (AT&SF), which showed some interest in the project. [6] [7]

Baldwin quad patent dwg.gif
Patent application drawing for the Baldwin quadruplex locomotive, 1913

Belgium

The only quadruplex locomotive built was No. 2096 for the National Railway Company of Belgium. The locomotive built by the Ateliers Métallurgiques de Tubize in Belgium was the first locomotive ever with Franco-Crosti boilers. The 0-6-2+2-4-2-4-2+2-6-0 locomotive consisted of three articulated sections with a total of four engines. The middle section, with two engines with four wheels each, carried the two steam boilers, which operated at 14 bar. They were arranged at a slight angle to allow the two fireboxes to be placed side by side in the centre. [8]

Coupe longitudinale et plan schematiques de la locomotive articulee Franco.png
Longitudinal section and schematic drawing of the articulated locomotive system Franco-Crosti for the National Railway Company of Belgium, 1932

The two end units each carried a Franko-Crosti flue gas preheater. The connections between the boilers in the centre section and the preheaters in the end sections were expected to have problems with outside air being drawn in by leakage, so the spherical connections were designed with labyrinth seals.

Belgian quadruplex steam locomotive No. 2096 SNCB 2096 Quadruplex Steam Locomotive with Franco-Crosti Boilers.png
Belgian quadruplex steam locomotive No. 2096

The water tanks were also in the end sections, which were driven by six-wheel engines. All engines were single-expansion engines. The 20 drivers were supplemented by 10 idlers. The total weight of the three-part locomotive was given as 230 t (according to other sources 248 t), the adhesion mass as 164 t. [8]

In the middle section were two identical cabs, which were used depending on the direction of travel, as the 29 m (31 m according to other sources) long locomotive could not use turntables due to its length. Each of the two boilers had its own coal box and was operated by its own fireman. The coal boxes were located to the side of the long boilers. While one fireman could communicate directly with the driver, the other fireman's line of sight to the driver was blocked by the coal box, so communication was by audible signals only. [8]

The locomotive was delivered in 1932, but was never actually used. The locomotive's tractive forces were so high that the chain couplers broke. The reason for building the locomotive is unclear, as it was far beyond the needs of the Belgian State Railways for freight transport, and could not be used for passenger transport due to its low top speed of 60 kph. The sheer size of the locomotives caused problems with stabling, the large number of coupling wheels, cylinders and seals on the movable connections between the preheaters and the main boilers were additional maintenance problems, apart from the fact that the locomotive required two firemen instead of one. The locomotive was exhibited at the 1935 Brussels World's Fair and was retired shortly afterwards. Some believe that the locomotive was built as a proof of concept for the project of a larger hexaplex locomotive with the same body for the Russian market. [9]

Super-Garratt

Beyer, Peacock and Company also applied for a patent for a quadruplex locomotive in 1927. Based on their successful Garratt locomotive design, it was called the Super-Garratt. The standard gauge locomotive was designed as an articulated 2-6-6-2+2-6-6-2 for the North American railroads and would have been built in conjunction with the American Locomotive Company (ALCo). [10] The starting tractive force of 200,000 pounds-force (890 kN) of the 460-ton locomotive would probably have been at the limit of the couplers in use at the time. Like a Garratt locomotive, it had a centre frame with boiler, firebox and cab, which sat on two subframes at each end. Each subframe, like a Mallett locomotive, contained a fixed set of driving wheels and, at the end of the locomotive, a pivoting bogie with another set of driving wheels. In addition to the standard gauge version, a 3 ft 6 in gauge version was planned for the South African Railways (SAR), but neither version was built. [11] [12] [ self-published source ]

Garratt quadruplex (rendering).jpg
Rendering of a Super Garratt locomotive
Garratt quadruplex (drawing).gif
Side view of a standard gauge Super Garratt locomotive

Quintuplex locomotives

A quintuplex version (2-8-8-8-8-8-2) was also included in the George R. Henderson's U.S. patent application for the quadruplex version. The design was based on the quadruplex, with the fourth and fifth engines under an extended, articulated tender. [6] [7] [13]

An even larger 2-10-10-10-10-10-2 variant appeared as an artist's impression in the August 1951 issue of Trains magazine. However, this idea seems to be speculative on the part of both the magazine writer and the artist, perhaps because AT&SF already had a fleet of 2-10-10-2’s in 1913. There is no evidence that either George Henderson or Baldwin suggested such a version.

Hexaplex locomotive

There was a Belgian project for a hexaplex locomotive for the Russian market, based on the Franco-Crosti quadruplex locomotive built for the Belgian State Railways. It had the wheel arrangement 2-4-4-2+2-8-8-2+2-4-4-2 and made full use of the Russian loading gauge and broad gauge. The total weight of the 43-metre-long locomotive was to be 410 tonnes, of which about 320 tonnes would have been available for adhesion. The water tank capacity was to be 60 m3, the coal capacity 15 tonnes. [14]

Belgisches Projekt einer Quadruplex-Lokomotive fur den russischen Markt.png
Longitudinal section and schematic drawing of the hexaplex locomotive system Franco-Crosti for the Russian market, 1930s

Related Research Articles

<span class="mw-page-title-main">Fairlie locomotive</span> Type of articulated locomotive

A Fairlie locomotive is a type of articulated steam locomotive that has the driving wheels on bogies. The locomotive may be double-ended or single ended. Most double-ended Fairlies had wheel arrangements of 0-4-4-0T or 0-6-6-0T.

<span class="mw-page-title-main">Whyte notation</span> Code for arrangement of locomotive wheels

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.

<span class="mw-page-title-main">Garratt locomotive</span> Articulated steam locomotive

A Garratt locomotive is a type of articulated steam locomotive invented by British engineer Herbert William Garratt that is articulated into three parts. Its boiler, firebox, and cab are mounted on a centre frame or "bridge". The two other parts, one at each end, have a pivot to support the central frame; they consist of a steam engine unit – with driving wheels, trailing wheels, valve gear, and cylinders, and above it, fuel and/or water storage.

<span class="mw-page-title-main">0-4-4-0</span> Locomotive wheel arrangement

In the Whyte notation for the classification of steam locomotive wheel arrangement, an 0-4-4-0 is a locomotive with no leading wheels, two sets of four driving wheels, and no trailing wheels. The arrangement is chosen to give the articulation of a locomotive with only the short rigid wheelbase of an 0-4-0, but with its weight spread across eight wheels, and with all the weight carried on the driving wheels; effectively a flexible 0-8-0. Articulated examples were constructed as Mallet, Meyer, BMAG and Double Fairlie locomotives and also as geared locomotives such as Shay, Heisler, and Climax types. A similar configuration was used on some Garratt locomotives, but it is referred to as 0-4-0+0-4-0. In the electric and diesel eras, the Bo-Bo is comparable and closest to the Meyer arrangement of two swivelling bogies.

Under the Whyte notation for the classification of steam locomotives by wheel arrangement, a 2-6-6-2 is a locomotive with one pair of unpowered leading wheels, followed by two sets of three pairs of powered driving wheels and one pair of trailing wheels. The wheel arrangement was principally used on Mallet-type articulated locomotives, although some tank locomotive examples were also built. A Garratt locomotive or Golwé locomotive with the same wheel arrangement is designated 2-6-0+0-6-2 since both engine units are pivoting.

Under the Whyte notation for the classification of steam locomotives, a 2-8-8-8-4 has two leading wheels, three sets of eight driving wheels, and four trailing wheels.

<span class="mw-page-title-main">4-6-2+2-6-4</span> Locomotive wheel arrangement

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, six powered and coupled driving wheels, and two trailing wheels.

<span class="mw-page-title-main">2-6-0+0-6-2</span> Garratt locomotive wheel arrangement

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<span class="mw-page-title-main">0-4-0+0-4-0</span> Locomotive wheel arrangement

Under the Whyte notation for the classification of steam locomotives by wheel arrangement, the 0-4-0+0-4-0 is an articulated locomotive of the Garratt type. The wheel arrangement is effectively two 0-4-0 locomotives operating back-to-back or face-to-face, with the boiler and cab suspended between the two power units. Each power unit has no leading wheels, four powered and coupled driving wheels on two axles and no trailing wheels. A similar arrangement exists for Mallet, Meyer and Fairlie locomotives, but is referred to as 0-4-4-0.

<span class="mw-page-title-main">Franco-Crosti boiler</span>

The Franco–Crosti boiler is a type of boiler used for steam locomotives. It was designed in the 1930s by Attilio Franco and Dr Piero Crosti. The main difference between it and conventional feedwater heaters widely used on the continent is that the Franco-Crosti boiler uses both exhaust steam and exhaust gases from the firebox. Conventional feedwater heaters only use exhaust steam.

Under the Whyte notation for the classification of steam locomotives by wheel arrangement, a 4-8-2+2-8-4 is a Garratt articulated locomotive consisting of a pair of 4-8-2 engine units back to back, with the boiler and cab suspended between them. The 4-8-2 wheel arrangement has four leading wheels on two axles, usually in a leading bogie, eight powered and coupled driving wheels on four axles and two trailing wheels on one axle, usually in a trailing truck. Since the 4-8-2 type is generally known as a Mountain, the corresponding Garratt type is usually known as a Double Mountain.

<span class="mw-page-title-main">2-6-2+2-6-2</span> Locomotive wheel arrangement

Under the Whyte notation for the classification of steam locomotives by wheel arrangement, 2-6-2+2-6-2 is an articulated locomotive using a pair of 2-6-2 power units back to back, with the boiler and cab suspended between them. The 2-6-2 wheel arrangement has a single pair of leading wheels in a leading truck, followed by three coupled pairs of driving wheels and a pair of trailing wheels in a trailing truck.

<span class="mw-page-title-main">2-8-2+2-8-2</span> Locomotive wheel arrangement

Under the Whyte notation for the classification of steam locomotives by wheel arrangement, a 2-8-2+2-8-2 is an articulated locomotive using a pair of 2-8-2 power units back to back, with the boiler and cab suspended between them. The 2-8-2 wheel arrangement has a single pair of leading wheels in a leading truck, followed by four coupled pairs of driving wheels and a pair of trailing wheels in a trailing truck. Since the 2-8-2 type was known as Mikado, the corresponding Garratt and Modified Fairlie types were usually known as Double Mikado.

<span class="mw-page-title-main">0-6-0+0-6-0</span> Locomotive wheel arrangement

Under the Whyte notation for the classification of steam locomotives, 0-6-0+0-6-0 represents the wheel arrangement of an articulated locomotive with two separate swivelling engine units, each unit with no leading wheels, six powered and coupled driving wheels on three axles and no trailing wheels. The arrangement is effectively two 0-6-0 locomotives operating back-to-back and was used on Garratt, Double Fairlie, Meyer and Kitson-Meyer articulated locomotives. A similar arrangement exists for Mallet steam locomotives on which only the front engine unit swivels, but these are referred to as 0-6-6-0.

Under the Whyte notation for the classification of steam locomotives by wheel arrangement, 2-4-0+0-4-2 is an articulated locomotive, usually of the Garratt type. The wheel arrangement is effectively two 2-4-0 locomotives operating back to back, with the boiler and cab suspended between the two power units. Each power unit has two leading wheels on one axle, four powered and coupled driving wheels on two axles and no trailing wheels. A similar wheel arrangement exists for Mallet locomotives, but is referred to as 2-4-4-2 since only the front engine unit can pivot.

<span class="mw-page-title-main">4-8-0+0-8-4</span> Garratt locomotive wheel arrangement

Under the Whyte notation for the classification of steam locomotives by wheel arrangement, the 4-8-0+0-8-4 is a Garratt articulated locomotive. The wheel arrangement is effectively two 4-8-0 locomotives operating back to back, with the boiler and cab suspended between the two engine units. Each engine unit has two pairs of leading wheels in a leading bogie, followed by four coupled pairs of driving wheels and no trailing wheels. A similar wheel arrangement exists for the Union Pacific Big Boy, but is referred to as 4-8-8-4 since only the front engine unit swivels.

<span class="mw-page-title-main">Triplex locomotive</span> Articulated steam locomotive with three sets of driving wheels

A triplex locomotive was a steam locomotive that divided the driving force on its wheels by using three pairs of cylinders to drive three sets of driving wheels. Any such locomotive will inevitably be articulated. All triplex locomotives built were of the Mallet type, but with an extra set of driving wheels under the tender. The concept was extended to locomotives with four, five or six sets of drive wheels. However, these locomotives were never built, except for one quadruplex locomotive in Belgium.

<span class="mw-page-title-main">Southern Railway (U.S.) Class Ms-2</span> American 2-6-0 + 2-8-0 experimental locomotives

Southern Railway's Class Ms-2 was a type of experimental steam locomotive.

Under the Whyte notation for the classification of steam locomotives by wheel arrangement, the 4-6-0+0-6-4 is a Garratt locomotive. The wheel arrangement is effectively two 4-6-0 ten-wheeler locomotives operating back to back, with the boiler and cab suspended between the two swivelling power units. Each power unit has two pairs of leading wheels in a leading bogie, followed by three coupled pairs of driving wheels and no trailing wheels.

Under the Whyte notation for the classification of steam locomotives, a 2-8-8-8-8-2 has two leading wheels, four sets of eight driving wheels, and two trailing wheels. Because of its length, such a locomotive must be an multiplex locomotive. It is longer than a normal articulated locomotive; the fourth set of drivers is located under the tender.

References

  1. 1 2 Self, Douglas. "Duplex Drive Locomotives". Unusual Locomotives. Retrieved 2023-10-29.
  2. ↑ "2-8-8-8-2/4 "Triplex" Locomotives in the USA". steamlocomotive.com. Archived from the original on 2016-06-24. Retrieved 2023-10-28.
  3. ↑ Westing, Frederick (1966), The locomotives that Baldwin built. Containing a complete facsimile of the original "History of the Baldwin Locomotive Works, 1831–1923", Crown Publishing Group, pp. 124–125, ISBN   978-0-517-36167-2, LCCN   66025422
  4. ↑ "2-8-8-8-2/4 "Triplex" Locomotives in the USA". www.steamlocomotive.com. Archived from the original on 2016-06-24.
  5. ↑ USpatent 1100563,Henderson, George,"Locomotive",issued 1914-06-16, assigned to Baldwin Locomotive Works
  6. 1 2 Solomon, Brian, 2015. The Majesty of Big Steam. Voyageur Press. ISBN   978-0760348925
  7. 1 2 Drury, George H. (1993). Guide to North American Steam Locomotives. Waukesha, Wisconsin: Kalmbach Publishing Company.
  8. 1 2 3 Valenziani, M.H (1933-03-25). "Nouveau type de locomotive à vapeur articulée à grande puisasance, système Franco". Le Génie civil (in French): 287.
  9. ↑ Belgium's completely overkill engine – Quadraplex on YouTube
  10. ↑ Hills, Richard Leslie (1982). Beyer, Peacock : locomotive builders to the world. p. 182.
  11. ↑ Leslie Paxton and David Bourne, Locomotive of the South African Railways, Struik, 1985, pp. 8–9.
  12. ↑ Self, Douglas. "Dreams of Quadraplexes".
  13. ↑ Trains. Kalmbach Publishing Company. 1950.
  14. ↑ Self, Douglas. "The Franco-Crosti Boiler System" . Retrieved 2023-09-07.

Bibliography

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