GWR 645 Class
Encyclopedia
The GWR 645 Class was a class of 0-6-0
saddle tank locomotives
designed by George Armstrong
and built at the Wolverhampton railway works
of the Great Western Railway
(GWR). Thirty-six were constructed between 1872-3, of which three were built for the South Wales Mineral Railway (SWMR), two for the Carmarthen and Cardigan Railway
(C&CR) and the remainder for the GWR. In essence they were saddle tank versions of his GWR 633 Class
of 1871. From 1878 a further 72 of the class, partially enlarged, were added in the 1501 numbering sequence. Unlike the originals, the "1501"s had full-length saddle tanks from the start.
The whole class was delivered in nine lots, as follows:
Three of the un-numbered engines plus No. 767 were sold to the SWMR, and the other two plus No.655 to the C&CR. The latter three returned to the GWR in 1881, becoming Nos. 902-904.
When built, they had 4' 6" driving wheel
s (later 4' 7½" due to thicker tyres) and 16", 16½" or 17" x 24" cylinders
. Half-cabs were added a few years after construction. From 1918 all but eight of the class were rebuilt with Belpaire fireboxes and larger, pannier tanks extending over the smokebox
, and the 17" diameter cylinders became standard. Most of the 645s and 1501s were allocated to the Northern Division of the GWR. Between 1910 and 1922 three more of them, Nos. 1806, 1811 and 1546, were transferred to the SWMR, and others too went to South Wales. Most were withdrawn in 1930s. Nos. 1531, 1532, 1538 and 1542 passed briefly into British Railways ownership, but all went by December 1949. None has survived into preservation.
0-6-0
Under the Whyte notation for the classification of steam locomotives, 0-6-0 represents the wheel arrangement of no leading wheels, six powered and coupled driving wheels on three axles, and no trailing wheels...
saddle tank locomotives
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 pulling it behind it in a tender. It will most likely also have some kind of bunker to hold the fuel. There are several different types of tank locomotive dependent upon...
designed by George Armstrong
George Armstrong (engineer)
George Armstrong was in charge of standard gauge steam locomotives for the Great Western Railway at Stafford Road Works, Wolverhampton from 1864 to 1897...
and built at the Wolverhampton railway works
Wolverhampton railway works
Wolverhampton railway works was in the city of Wolverhampton in the county of Staffordshire, England. It was almost due north of the city centre, and is commemorated with a small display of level crossing gates and a plaque...
of the Great Western Railway
Great Western Railway
The Great Western Railway was a British railway company that linked London with the south-west and west of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament in 1835 and ran its first trains in 1838...
(GWR). Thirty-six were constructed between 1872-3, of which three were built for the South Wales Mineral Railway (SWMR), two for the Carmarthen and Cardigan Railway
Carmarthen and Cardigan Railway
The Carmarthen and Cardigan Railway was a broad gauge railway from Carmarthen, Carmarthenshire, to Newcastle Emlyn, Wales. Part of the route is now used by the Teifi Valley Railway and the Gwili Railway.Despite the name, the line never reached Cardigan...
(C&CR) and the remainder for the GWR. In essence they were saddle tank versions of his GWR 633 Class
GWR 633 Class
Class 633 of the Great Western Railway consisted of ten 0-6-0 tank locomotives built by George Armstrong at the Wolverhampton works of the Great Western Railway in 1871-2. Unusually, they had side tanks, and inside frames, with wheels of 4'6 1/2" diameter and a wheelbase of 15'6". They were...
of 1871. From 1878 a further 72 of the class, partially enlarged, were added in the 1501 numbering sequence. Unlike the originals, the "1501"s had full-length saddle tanks from the start.
The whole class was delivered in nine lots, as follows:
- 645-655, plus one (Lot O, 1872)
- 656, 757-763, plus four (Lot P, 1872-3)
- 764-775 (Lot Q, 1873)
- 1501-1512 (Lot A2, 1878)
- 1513-1524 (Lot B2, 1878-9)
- 1525-1536 (Lot D2, 1879)
- 1537-1548 (Lot E2, 1879-80)
- 1549-60 (Lot F2, 1880)
- 1801-1812 (Lot G2, 1881)
Three of the un-numbered engines plus No. 767 were sold to the SWMR, and the other two plus No.655 to the C&CR. The latter three returned to the GWR in 1881, becoming Nos. 902-904.
When built, they had 4' 6" driving wheel
Driving wheel
On a steam locomotive, a driving wheel is a powered wheel which is driven by the locomotive's pistons...
s (later 4' 7½" due to thicker tyres) and 16", 16½" or 17" x 24" cylinders
Cylinder (engine)
A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...
. Half-cabs were added a few years after construction. From 1918 all but eight of the class were rebuilt with Belpaire fireboxes and larger, pannier tanks extending over the smokebox
Smokebox
A smokebox is one of the major basic parts of a Steam locomotive exhaust system. Smoke and hot gases pass from the firebox through tubes where they pass heat to the surrounding water in the boiler. The smoke then enters the smokebox, and is exhausted to the atmosphere through the chimney .To assist...
, and the 17" diameter cylinders became standard. Most of the 645s and 1501s were allocated to the Northern Division of the GWR. Between 1910 and 1922 three more of them, Nos. 1806, 1811 and 1546, were transferred to the SWMR, and others too went to South Wales. Most were withdrawn in 1930s. Nos. 1531, 1532, 1538 and 1542 passed briefly into British Railways ownership, but all went by December 1949. None has survived into preservation.