Triplex locomotive

Last updated
The Erie Matt H. Shay 2-8-8-8-2 Erie Railroad - 2603 steam locomotive (Baldwin 2-8-8-8-2) (27197514215).jpg
The Erie Matt H. Shay 2-8-8-8-2
The only 2-8-8-8-4 triplex locomotive ever built 28884.jpg
The only 2-8-8-8-4 triplex locomotive ever built

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.

Contents

Triplex classes

Baldwin Locomotive Works built three 2-8-8-8-2 triplex locomotives for the Erie Railroad between 1914 and 1916. The first was named Matt H. Shay, after a beloved employee of that road. [1] These Triplexes were given the classification of P-1 and they could reportedly pull 650 freight cars. [2] The triplexes were primarily used as pushers on grades requiring helper locomotives. Slow moving, the triplexes were not considered highly successful, and no more were built for Erie. The Erie Railroad scrapped their Triplexes from 1929, 1931, and 1933. [1]

Another very similar designed triplex was built by Baldwin as a 2-8-8-8-4 for the Virginian Railway, as No. 700, in 1916. This triplex was given classification of XA, so named due to the experimental nature of the locomotive. The 2-8-8-8-4 was considered unsuccessful because it only made a maximum speed of 4.8–8.0 km/h (3–5 mph) and had high maintenance costs. The XA 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. These two engines were in service until 1953. [3] Both of the two engines were scrapped.[ citation needed ]

Design

The triplex locomotives were of the Mallet type, but with an extra set of driving wheels under the tender. The centre set of cylinders received high-pressure steam. The exhaust from these was fed to the two other sets of cylinders. [1] The right cylinder exhausted into the front set of low pressure cylinders, and the left into the rear set; this is also why the high pressure cylinders are the same diameter as the low pressure cylinders, making the engine a 2 to 1 compound, whereas most Mallet locomotives have much smaller high pressure cylinders. The front set exhausted through the smokebox and the rear set exhausted first through a feedwater heater in the tender and then through a large pipe directly to the outside, as can be seen in the photo. As only half of the exhaust steam went through the blast pipe in the smokebox, the draft in the firebox and the heating of the boiler was poor. Although the boiler was large in comparison with contemporary two-cylinder and four-cylinder locomotives, six large cylinders required more steam than even such a boiler could supply. [1]

The Erie locomotives always operated in compound mode and did not have starting valves that would have put full pressure on all six cylinders, yet the triplexes produced huge amounts of tractive effort that may have been the highest of any steam locomotives ever. Westing [1] gives a figure of 160,000 lbf (710 kN) in compound mode and seems to indicate that it was the largest tractive effort for any locomotives up to the mid-1910s. The Union Pacific Big Boy, built in the 1940s, did not exceed the tractive effort of the Erie locomotives either, as it had a tractive effort of only 135,375 lbf (602.18 kN).

The triplexes could also be considered the largest tank locomotives ever built, as the tender also had driving wheels and thus contributed to the traction. The problem of variable adhesion of the tender unit was not a serious one, as the pusher locomotives had frequent opportunities to take on additional fuel and water.

Usage

In all, only four triplex locomotives were built, and only in the United States. Because the tractive effort of the locomotives was so great that the couplings and frames of the cars could not withstand it, [4] the triplex locomotives could only be used to bank [1] heavy trains up steep grades. Even with their huge boilers, the Erie locomotives could only produce enough steam to run at 16 km/h (10 mph), the Virginian only 8.0 km/h (5 mph). [4] The reason for this was the poor performance of the boilers due to the lack of exhaust draught from the driving wheelset under the tender. [5]

The Erie locomotives were used as helpers on the Susquehanna Hill also known as the Gulf Summit, near Deposit, New York, on the Southern Tier Line. After 13 years they were replaced by 2-10-2s and retired. [4] All Erie triplex locomotives had been scrapped by 1930, and none has survived.

Virginian Railway Class AF -610.jpg

The Virginian XA #700 2-8-8-8-4 was unsuccessful. It was returned to Baldwin, where it was rebuilt into a 2-8-2, numbered 410, and a 2-8-8-0, numbered 610. A two-wheel trailing truck was later added, making it into a 2-8-8-2. These two locomotives were operated until 1953. [4]

Related Research Articles

<span class="mw-page-title-main">Steam locomotive</span> Railway locomotive that produces its pulling power through a steam engine

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.

<span class="mw-page-title-main">Mallet locomotive</span> Articulated locomotive with compound steam power

A Mallet locomotive is a type of compound articulated steam locomotive, invented by the Swiss engineer Anatole Mallet (1837–1919).

<span class="mw-page-title-main">Steam locomotive components</span> Glossary of the main components of a typical steam locomotive

Main components found on a typical steam locomotive include:

Under the Whyte notation for the classification of steam locomotive wheel arrangements, a 2-10-10-2 is a locomotive with two leading wheels, two sets of ten driving wheels, and a pair of trailing wheels.

<span class="mw-page-title-main">4-8-8-2</span> Articulated locomotive wheel arrangement

Under the Whyte notation for the classification of steam locomotives, a 4-8-8-2 is a locomotive with four leading wheels, two sets of eight driving wheels, and a two-wheel trailing truck.

Under the Whyte notation for the classification of steam locomotives, a 2-8-8-8-2 has two leading wheels, three sets of eight driving wheels, and two trailing wheels. Because of its length, such a locomotive must be an articulated locomotive. It is not longer than a normal articulated; the third set of drivers is located under the tender. All of the examples produced were a Triplex of the Mallet type.

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">Steam turbine locomotive</span>

A steam turbine locomotive is a steam locomotive which transmits steam power to the wheels via a steam turbine. Numerous attempts at this type of locomotive were made, mostly without success. In the 1930s this type of locomotive was seen as a way both to revitalize steam power and challenge the diesel locomotives then being introduced.

<span class="mw-page-title-main">South African Class 18 2-10-2</span>

The South African Railways Class 18 2-10-2 of 1927 was a steam locomotive.

<span class="mw-page-title-main">South African Class KM 0-6-0+0-6-0</span>

The South African Railways Class KM 0-6-0+0-6-0 of 1904 was an articulated steam locomotive from the pre-Union era in Transvaal Colony.

<span class="mw-page-title-main">South African Class MA 2-6-6-0</span>

The South African Railways Class MA 2-6-6-0 of 1909 was a steam locomotive from the pre-Union era in the Natal Colony.

<span class="mw-page-title-main">South African Class MB 2-6-6-0</span>

The South African Railways Class MB 2-6-6-0 of 1910 was a steam locomotive from the pre-Union era in the Colony of Natal.

The South African Railways Class MC 2-6-6-0 of 1912 was a steam locomotive.

<span class="mw-page-title-main">South African Class MC1 2-6-6-0</span>

The South African Railways Class MC1 2-6-6-0 of 1914 was a steam locomotive.

<span class="mw-page-title-main">South African Class MD 2-6-6-2</span>

The South African Railways Class MD 2-6-6-2 of 1910 was a steam locomotive from the pre-Union era in Transvaal.

The South African Railways Class ME 2-6-6-2 of 1912 was a steam locomotive.

The South African Railways Class MG 2-6-6-2 of 1911 was a steam locomotive from the pre-Union era in Transvaal.

The South African Railways Class GA 2-6-0+0-6-2 of 1921 was an articulated steam locomotive.

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 articulated locomotive. It is not longer than a normal articulated; the fourth set of drivers is located under the tender.

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.

References

  1. 1 2 3 4 5 6 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
  2. ↑ "A titan of the rails". The Independent. July 27, 1914. Retrieved July 24, 2012.
  3. ↑ "2-8-8-8-2/4 "Triplex" Locomotives in the USA". www.steamlocomotive.com. Archived from the original on 2016-06-24.
  4. 1 2 3 4 "2-8-8-8-2/4 "Triplex" Locomotives in the USA". steamlocomotive.com. Archived from the original on 2016-06-24. Retrieved 23 October 2023.
  5. ↑ M.T.H. Electric Trains (ed.). "HO 2-8-8-8-2 Triplex". Modèles Européens 2011 (in French). Columbia (MD): 11. Retrieved 23 October 2023.

Patent

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.