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.
The first locomotive, No. 3373, was named Atbara and all the locomotives of Lots 125 & 126, which have the standard depth of framing, are known as the Atbara class. The later engines of Lot 176, which have deeper frames, were given the names of flowers and are known as the Flower class.
The first ten engines of Lot 125 had a very high cab, whereas the remaining members of this lot had a standard height cab with a much smaller cut-out in the side sheets. Lots 126 and 176 had a standard height cab. Lot 125 differed from the later locomotives because of the curved rear steps.
Two boilers are provided in the kit the D2 half coned and the D3 three-quarter coned. This means that Lots 125 and 126 cannot be built in their original condition with the DO parallel boiler but can be built in slightly later condition, from 1904 onwards when they were fitted with the D2 and D3 boilers. Lot 176 were built with the D3 boiler although several subsequently carried D2 boilers, Nos. 4155 & 4164 as late as 1920. The engines rebuilt as Cities, with the larger No. 4 boiler, cannot be built from the kit in that form although several were fitted with the D2 or D3 boilers provided, before they became Cities, and so could be built in this form from the kit.
Atbaras originally had Dean 'swing-hanger' bogies with shallow framing, fluted coupling rods, steam brake and steam reverse whereas the Flowers were built with 'De Glehn' type bogies, plain coupling rods, vacuum brake and screw reverse. It is believed that all of the Atbaras were later rebuilt with screw reverse, the RCTS book stating 'quite a number' had been fitted by 1924.
There are also many detail differences both between individual locomotives and as the class changed through time.
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.
Frame strengthening. The locomotives acquired frame strengthening plates surprisingly quickly, probably during their first major shopping. Atbaras were first fitted with separate plates for each axle. Later larger, one piece plates were fitted to some of the class. The Flowers quickly acquired plates to the rear axle only.
Smokebox. Originally quite short and later front and back rings riveted.
Smokebox saddle. Early flush rivets, later snap head rivets.
Sandboxes. Originally fitted below the footplate on the leading coupled wheels only. Later, all except No. 4138, larger sandboxes were fitted above the footplate on all driving wheels. The Flowers were built with the larger type.
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 visible.
Leading coupled wheel splasher. The Atbaras were built with a beaded splasher, below the footplate, on the leading coupled axle which were gradually removed by WW1.
Cab spectacle windows. Plated over during the late 1920's.
Vacuum pipe. Originally tall, later a shorter pattern was introduced.
When built most of the Atbaras were fitted with standard Dean 3000 gallon tenders with a few fitted with Dean 4000 gallon tenders. The Flowers were built with Churchward 3500 gallon tenders and some of the Atbaras subsequently acquired these tenders whilst a few of the Flowers received 3000 gallon tenders.
Bogie wheels - 3’ 8" diameter, 10 spoke, 5/32” diameter axle Slater's Ref. 7843SWMF
Driving wheel - 5’ 8", 18 spoke, 3/16" diameter axle (4) Slater's Ref.7868W
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.