The 3521 Class were forty

tank locomotive 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 (or fuel tanks) to hold fuel; in a tender-tank locom ...

s designed by William Dean to haul passenger trains on the Great Western Railway. They were introduced as

0-4-2T T, or t, is the twentieth letter in the modern English alphabet and the ISO basic Latin alphabet. Its name in English is ''tee'' (pronounced ), plural ''tees''. It is derived from the Semitic letters taw (ת, ܬ, ت) via the Greek letter ...

locomotives in 1887, but were quickly altered to become

0-4-4T Under the Whyte notation for the classification of steam locomotives, 0-4-4 represents the wheel arrangement of no leading wheels, four powered and coupled driving wheels on two axles, and four trailing wheels on two axles. This type was only used ...

s to improve their running. Following two serious accidents they were further altered from 1899 to run as 4-4-0

tender locomotive A tender or coal-car (US only) is a special rail vehicle hauled by a steam locomotive containing its fuel (wood, coal, oil or torrefied biomass) and water. Steam locomotives consume large quantities of water compared to the quantity of fuel, s ...

s, in which form the last was withdrawn in 1934.

Locomotives

0-4-2T standard gauge

The first twenty locomotives were turned out in 1887 as

locomotives for services on the lines. * 3521 * 3522 * 3523 * 3524 * 3525 * 3526 * 3527 * 3528 * 3529 * 3530 * 3531 * 3532 * 3533 * 3534 * 3535 * 3536 * 3537 * 3538 * 3539 * 3540

0-4-2T broad gauge

In 1888 a further batch of twenty were ordered as

0-4-2 Under the Whyte notation for the classification of steam locomotives, represents the wheel arrangement with no leading wheels, four powered and coupled driving wheels on two axles and two trailing wheels on one axle. While the first locom ...

ST saddle tanks for the broad gauge lines in

Devon Devon ( , historically known as Devonshire , ) is a ceremonial and non-metropolitan county in South West England. The most populous settlement in Devon is the city of Plymouth, followed by Devon's county town, the city of Exeter. Devo ...

and

Cornwall Cornwall (; kw, Kernow ) is a historic county and ceremonial county in South West England. It is recognised as one of the Celtic nations, and is the homeland of the Cornish people. Cornwall is bordered to the north and west by the Atlantic ...

. * 3541 (1888 - 1890) * 3542 (1888 - 1891) * 3543 (1888 - 1891) * 3544 (1888 - 1890) * 3545 (1888 - 1891) * 3546 (1888 - 1890) * 3547 (1888 - 1891) * 3548 (1888 - 1891) * 3549 (1888 - 1891) * 3550 (1888 - 1890) * 3551 (1888 - 1890) * 3552 (1888 - 1890) * 3553 (1888 - 1890) * 3554 (1889 - 1891) * 3555 (1889 - 1890) * 3556 (1889 - 1890) * 3557 (1889 - 1891) * 3558 (1889 - 1890) * 3559 (1889 - 1890)

0-4-4T broad gauge

Due to the unsteady running of the 0-4-2STs, the last of the order, 3560, was turned out in August 1889 as a 0-4-4T bogie side tank. The remainder of the class were altered to a similar layout over the following two years. 3560 was slightly different at this time, having a bogie that was shorter and an overall wheelbase of , rather than the of the converted locomotives. * 3541 (1890 - 1892) * 3542 (1891 - 1892) * 3544 (1890 - 1892) * 3545 (1891 - 1892) * 3546 (1890 - 1892) * 3548 (1891 - 1892) * 3549 (1891 - 1892) * 3550 (1890 - 1892) * 3551 (1890 - 1892) * 3552 (1890 - 1892) * 3553 (1890 - 1892) * 3554 (1891 - 1892) * 3555 (1890 - 1892) * 3556 (1890 - 1892) * 3557 (1891 - 1892) * 3558 (1890 - 1892) * 3559 (1890 - 1892) * 3560 (1889 - 1892)

0-4-4T standard gauge

The standard gauge 0-4-2Ts were converted to 0-4-4Ts in the same manner as the broad gauge locomotives, which were all eventually converted to standard gauge. By the end of 1892 the whole class of forty locomotives was to one standard design for the first time. * 3521 * 3522 * 3523 * 3524 * 3525 * 3526 * 3527 * 3528 * 3529 * 3530 * 3531 * 3532 * 3533 * 3534 * 3535 * 3536 * 3537 * 3538 * 3539 * 3540 * 3541 (1892 - ) * 3542 (1892 - ) * 3543 (1891 - ) * 3544 (1892 - ) * 3545 (1892 - ) * 3546 (1892 - ) * 3547 (1891 - ) * 3548 (1892 - ) * 3549 (1892 - ) * 3550 (1892 - ) * 3551 (1892 - ) * 3552 (1892 - ) * 3553 (1892 - ) * 3554 (1892 - ) * 3555 (1892 - ) * 3556 (1892 - ) * 3557 (1892 - ) * 3558 (1892 - ) * 3559 (1892 - ) * 3560 (1892 - 1899)

4-4-0 standard gauge

All forty

locomotives were rebuilt as 4-4-0 tender locomotives between 1899 and 1902. Twenty-six locos retained their parallel domed boilers while fourteen received new Standard No 3 parallel domeless boilers (later replaced by the taper barrel version of that type). (Holcroft states that twenty-six received Standard No 3 boilers.) Holcroft was of the opinion that the original inside and outside frames were modified whereas Le Fleming was of the opinion that new inside frames would have been required. However, as the modification also increased the coupled wheelbase from 7 ft 4 in to 8 ft 6 in it is unlikely that much of the original framing was re-used. Two locomotives, 3521 and 3546, were transferred to the Cambrian Railways in 1921 to replace locomotives destroyed in the Abermule accident. They were allocated Cambrian numbers 82 and 95 respectively but these were never carried, the two locomotives being returned to the Great Western Railway with their original numbers when the two railways were grouped together in 1922.

Accidents and incidents

*On 13 April 1895, locomotives 3536 and 3537, hauling the ''Cornishman'', exceeded the speed limit by , damaging the track. A passenger train hauled by 3521 and 3548 consequently derailed between and

Bodmin Road Bodmin Parkway railway station ( kw, Fordh Bosvena) is on the Cornish Main Line that serves the nearby town of Bodmin and other parts of mid-Cornwall, England. It is situated south-east of the town of Bodmin in the civil parish of St Winnow, ...

. *In 1898, locomotive 3542 derailed near

Penryn, Cornwall Penryn (; kw, Pennrynn, meaning 'promontory') is a civil parish and town in west Cornwall, England, United Kingdom. It is on the Penryn River about northwest of Falmouth. The population was 7,166 in the 2001 census and had been reduced to ...

whilst hauling a mail train. The locomotive rolled down an embankment, killing the driver. The accident was caused by a combination of the condition of the track and the locomotive oscillating. Following this the whole class was rebuilt as 4-4-0 tender locomotives.

References

* * * * * {{GWR Locomotives 3521 Broad gauge (7 feet) railway locomotives 0-4-2T locomotives 0-4-4T locomotives 4-4-0 locomotives Railway locomotives introduced in 1887 Standard gauge steam locomotives of Great Britain Scrapped locomotives Passenger locomotives