I feel it is time for an update on progress with my model of GWR No.184. After a rather static period, when I did little actual modelling but thought quite a lot about the details of this engine, I have at last been cutting metal.
In fact, apart from the fact that it is now made of brass, I have made few changes to my initial paper template. My method of construction followed that used on my first scratch-built model (GWR 'Queen'-class - described in Railway Modeller July 2014). In summary, I cut out the components from scale paper drawings and stuck these (using a glue stick) to 10 thou (0.25 mm) brass sheet.
One simplification that I made, following experience with 'Queen' was not to make a double-fold in the main chassis in order to mount the splasher fronts, but instead to provide tabs on the splashers 'module', to fold under the chassis sides. The main components that make up the body look like this:
As before, I had little difficulty with rolling the boiler, although I suspect that it helped to have a paper layer stuck to the outside of the brass sheet while rolling. This seemed to help with the smoothness of the curvature and also protected the surface of the brass from scratching. Since the prototype boiler had a diameter of 4' 2", I calculated the scale circumference (3.142 x diameter) and then cut out a rectangle of brass, to roll into a cylinder. I made this tube the full length of firebox + boiler + smokebox, to provide a rigid structure and then added the raised firebox and smokebox as simple wrappers. The stages in assembly are shown below:
I used a diamond slitting disk on my mini-drill to open up the apertures for the wheels in the floor plate. For the photograph, I've just rested a chimney and safety-valve cover in place, to make it look a bit like a locomotive (!) and have not bought a dome yet - probably a 517-type. The next step will be to fit 'cosmetic' outside frames with embossed rivet detail and then use thin (5 thou - 0.125 mm) brass sheet, to form the curved running plates between the outside frames and the splasher fronts.
Anyone who read my last post on this engine might remember that I had planned to begin with the chassis but, in the end, I decided to repeat the part that was already familiar, having done a very similar body for 'Queen'. I may produce a simple rolling chassis that can be pushed along by my 2,500 gal. motorised tender. I find that tackling a job in easy stages helps to keep up motivation, when I see the outline of an engine start to appear, and allows me to consider different options as I start to add the details.
So far, the outlay on brass sheet has been minimal but costs start to rise once all the detailing components are added, especially wheels, gearbox, and motor. At this stage, I feel that there is a reasonable chance of producing a model that will have at least a passing resemblance to its prototype.
GWR No.184 in 'Wolverhampton' livery
As an aside, I have mentioned before that many interesting old books can be downloaded from the Internet Archive website. I recently found that Ahrons' classic 'The British Steam Railway Locomotive 1825 - 1925' can be downloaded and, although I have a facsimile copy, it is useful to be able to copy drawings directly from the digital version. Another interesting find was Sekon's 'The Evolution of the Steam Locomotive 1803 - 1898', which has lots of fascinating detail about many very early engines, and many anecdotes about events during their trials and early use.