The LNWR Dreadnought class was a class of 40 passenger three-cylinder

compound Compound may refer to: Architecture and built environments * Compound (enclosure), a cluster of buildings having a shared purpose, usually inside a fence or wall ** Compound (fortification), a version of the above fortified with defensive struct ...

2-2-2-0 locomotives designed by

F. W. Webb Francis William Webb (21 May 1836 – 4 June 1906) was an English railway engineer, responsible for the design and manufacture of locomotives for the London and North Western Railway (LNWR). Webb was born in Tixall Rectory, near Stafford, th ...

for the

London and North Western Railway The London and North Western Railway (LNWR, L&NWR) was a British railway company between 1846 and 1922. In the late 19th century, the L&NWR was the largest joint stock company in the United Kingdom. In 1923, it became a constituent of the ...

, and manufactured by them in their

Crewe Works Crewe Works is a British railway engineering facility located in the town of Crewe, Cheshire. The works, which was originally opened by the Grand Junction Railway in 1840, employed around 7,000 to 8,000 workers at its peak. In the 1980s, a lo ...

between 1884 and 1888. The railway also commissioned the

Beyer, Peacock and Company Beyer, Peacock and Company was an English railway locomotive manufacturer with a factory in Openshaw, Manchester. Founded by Charles Beyer, Richard Peacock and Henry Robertson, it traded from 1854 until 1966. The company exported locomotives, a ...

to construct an additional locomotive of the design for the

Pennsylvania Railroad The Pennsylvania Railroad (reporting mark PRR), legal name The Pennsylvania Railroad Company also known as the "Pennsy", was an American Class I railroad that was established in 1846 and headquartered in Philadelphia, Pennsylvania. It was named ...

.Nock, O. S., et al. Railways at the Turn of the Century, 1895-1905. Blandford P., 1969.

Design

The design featured a boiler pressed to delivering saturated steam to two outside high-pressure cylinders, which exhausted to one low-pressure cylinder inside the frames. All three cylinders had a stroke of ; the high-pressure cylinders drove the rear wheels, while the low-pressure drove the leading driving wheels. As the two pairs of driving wheels were not connected, the locomotives were "

duplex drive DD or Duplex Drive tanks, nicknamed "Donald Duck tanks", were a type of amphibious swimming tank developed by the British during the Second World War. The phrase is mostly used for the Duplex Drive variant of the M4 Sherman medium tank, that was ...

" or "double-singles". They were a development of Webb's Experiment class; they had larger boilers and smaller driving wheels, and while the Joy valve gear for the HP and LP cylinders could still be independently adjusted, it was now also possible to reverse both sets simultaneously. The inside valve gear was subsequently amended to the loose or slip-eccentric system, thus giving automatic reversal.

Decline

When

George Whale George Whale (7 December 1842 – 7 March 1910) was an English locomotive engineer who was born in Bocking, Essex, and educated in Lewisham, London. He worked for the London and North Western Railway (LNWR). Career In 1858 he entered the LNWR's ...

become

chief mechanical engineer Chief mechanical engineer and locomotive superintendent are titles applied by British, Australian, and New Zealand railway companies to the person ultimately responsible to the board of the company for the building and maintaining of the locomotiv ...

of the LNWR in 1903, he started a programme of eliminating Webb's over-complicated duplex compound locomotives. Consequently, the class was scrapped between December 1903, and July 1905, having been replaced by Whale's Experiment class.

References

* * Morandière, Jules (1885). "Locomotive compound de M. Webb, modèle de 1884 pour trains rapides et lourds", Revue Générale des Chemins de fer et des Tramways, VII. Dunod éditeur, pp.75-79, fig. VI. {{LNWR Locomotives

Dreadnought The dreadnought (alternatively spelled dreadnaught) was the predominant type of battleship in the early 20th century. The first of the kind, the Royal Navy's , had such an impact when launched in 1906 that similar battleships built after her ...

2-2-2-0 locomotives Railway locomotives introduced in 1884 Compound locomotives Standard gauge steam locomotives of Great Britain Duplex locomotives