The prototype of this most famous of GWR 4-4-O classes was the 'Atbara' class engine Mauritius, rebuilt with the larger Standard No. 4 boiler in September 1902. Ten new engines followed in 1903 and nine more 'Atbaras' were similarly rebuilt in 1907-9.
For a detailed history of these classes, Part Seven of 'The Locomotives of the Great Western Railway' published by the RCTS is essential reading. Also useful are G.W.Engines Vol 2 by J.H.Russell, Standard Gauge G.W. 4-4-O's by O.S.Nock & Locomotives Illustrated 50 GWR double-framed 4-4-O's.
Chimneys. Three different types are provided.
Safety valve casing. Caters for with or without top-feed.
Bogies. Many rebuilt to 'De Glehn' type without swing-hangers and fitted with strengthening patches. Some built with beaded bogie splashers.
Coupling Rods. These locomotives were built with fluted rods but many were subsequently fitted with plain rods.
Frame strengthening. The locomotives acquired frame strengthening plates surprisingly quickly, probably during their first major shopping around 1904-1906. They were first fitted with separate plates for each axle. Later larger, one piece plates were fitted to some of the class.
Smokebox. Originally quite short. Later front and back rings had snap head rivets.
Smokebox saddle. Early flush rivets, later snap head rivets.
Sandboxes. Originally fitted below the footplate on the leading coupled wheels only. Later larger sandboxes were fitted above the footplate on all driving wheels.
Cab roof. Initially a canvas covered wood affair, later changed to steel with two designs of rainstrip.
Splashers. Initially built with beading, later the beading was removed and rivets were visible.
Leading coupled wheel splasher. Originally the locomotives were built with a beaded splasher, below the footplate, on the leading coupled axle which was gradually removed up to WW1.
Cab spectacle windows. Plated over during the late 1920's.
Vacuum pipe. Originally tall, later a shorter pattern was introduced.
When built the 'Cities' were fitted with standard Dean 3000 gallon tenders. Subsequently some acquired Churchward 3500 gallon tenders.
Bogie wheels - 3’ 8" diameter, 10 spoke, 5/32” diameter axle Slater's Ref. 7843SWMF
Driving wheels - 5’ 8", 18 spoke, 3/16" diameter axle (2) Slater's Ref. 7868O/C Extended axles with outside cranks
Motor/Gearbox. A Canon motor with a SDMP 40L/15 gearbox (available from Finney7) or an alternative such as an ABC VML2 gearbox.
Crankpins. Heavy duty crankpins are available from Finney7.
Inside Motion. A separate kit is available from Finney7 to construct the working inside motion.
Name Plates. A range of name plates are available from Finney7. Please enquire.
To obtain a pdf copy of the instructions please click on the links below; the pdf will open in a new window. Unfortunately the A4 and A3 pages have to be in different files.