I hadn’t intended to make another model so soon after my previous post but, having read about ‘Vulcan’ being the first engine in steam on the GWR, on 28th December 1837, I felt I should add it to my collection.

 

Since 'Vulcan' was a sister engine to 'Aeolus', which I have already modelled, I could re-use many of the parts I had already designed, so this was a fairly quick re-build.

 

My model of 'Aeolus' was based on the 1843 rebuild of the prototype, after the original version proved to be a poor performer with a loaded train. The rebuild involved new cylinders and smaller driving wheels. With these modifications, 'Aeolus' proved to be a useful branch-line engine, surviving until near the end of the broad gauge era.

 

'Vulcan' was also re-built, in this case as a tank engine, with the tank adding much-needed adhesion weight. In this form it even featured in an early photograph, as shown below:

 

Vulcan re-built as a tank engine

 

Fortunately, we also have a sketch by that most valuable source, E.T. Lane, of this engine in its original form:

 

 

This sketch shows that the appearance was little changed by the addition of the back-tank and bunker. I’m not sure why Lane showed such a ‘stunted’ chimney, since I feel the original would have been of similar height to other engines of the period – perhaps it was something very simple, such as having reached the edge of the page in his notebook?.

 

One point of interest is that comparative measurement between the wheelbase and driving wheel diameter, in both the photograph and Lane’s sketch, indicate a driving-wheel diameter of 7 feet. Many sources state that the diameter was 8 feet, when the engine was delivered, but it may have been altered quite early in its life, as were many others out of that initial batch of engines.

 

I overlaid the sketches of 'Vulcan' and 'Aeolus' to check how many parts I would need to modify from those made for 'Aeolus', Luckily, the answer was “not very many”

 

 

The boiler fittings on 'Vulcan' were different, with two domes, but it appears that the same frames were retained and simply lowered, when smaller wheels were fitted to 'Aeolus'. As a result, I found that I could re-use the boiler, smokebox, firebox, and frames from my previous model. I needed new driving wheels and splashers, and a new selection of boiler fittings.

 

As an aside, it appears that, when G.F. Bird made his much later drawings for ‘The Engineer’, he copied the safety valve and Salter spring from the original version and added them onto the 'Aeolus' re-build – thus providing duplicate Salter springs. Lane’s contemporary drawings do not show this duplication and I believe are more likely to be correct. A reminder to use contemporary sources whenever possible!

 

I created the new parts by using the methods I have already described in previous posts, and then brought my original and new parts together, to create a 3D model of 'Vulcan' in Fusion 360, as shown below:

 

My 3D-model of 'Vulcan', based on sketch by E.T. Lane

 

Because the modifications were minor, I was able to complete the amendments in ‘Fusion 360’ within an afternoon’s modelling.

 

Printing

 

Drawing on experience gained from earlier models I combined some of the smaller parts with larger ones, to reduce the amount of fiddly assembly-work needed after printing. Thus, the springs are combined with frames and the curved supports are integral with smokebox and firebox.

 

The printed ‘kit of parts’ is shown below:

 

3D-printed components of my Vulcan model

 

Following my usual method, the boiler, smokebox and firebox were assembled by sliding them over a brass tube to form a reasonably weighty rigid component.  For the chassis I first set up the inside frames, linked by the buffer beam at the front and the footplate at the rear, The wheels, set on pin-point axles were slotted into the horn-guides and the outside frames were added in alignment with the axles. There is sufficient ‘flex’ in the outside frames to allow the driving axle to be inserted into the horn-guides above the frames.

 

This structure is adequate for a static model but the chassis is rather too flexible for a working model, since I made many of the frame sections rather too thin, in order to keep the slender appearance of the prototype. To make this into a working model, I would have to add brass inner frames, as on my earlier model of ‘Fire Fly’.

 

Painting

 

I painted the various components separately, so minimising the need for masking between differently coloured parts. One advantages from having the central tube through boiler, smokebox and firebox is that it provides a useful finger-hold during painting!

 

Finger hold and ‘Pringles’ palette

 

I usually use artists’ acrylic paints, wetting the surfaces first, with an alcohol(IPA)/water mix, and then adding pigment to achieve the depth of colour I require. I mix colours such as vermilion for the buffer beam on a ‘Pringles’-lid palette!

 

Comparisons

 

One of my objectives in modelling these early locomotives was to gain a better understanding of locomotive development during the so-called ‘primitive’ period.

 

Gooch, in his ‘diaries’ recalled, of the engines he had in 1838, that “The North Star and the six from the Vulcan Foundry Company were the only ones I could at all depend upon. The result was I had to begin in a measure to rebuild one half of the stock I had to work with. For many weeks my nights were spent in a carriage in the engine-house at Paddington, as repairs had to be done to the engines at night to get them to do their work next day.” Yet, by 1840, Gooch could write “I was much more comfortable with regard to our engines; the new engines ordered to my drawings were being delivered. The Firefly, started on March 1840, was the first, and they all gave every one general satisfaction. We could now calculate with some certainty, not only upon the speed they could run, but also upon their not breaking down upon the journey.” My models trace the progress in those few years.

 

Here is ‘Vulcan’, fresh from the paint shop:

 

My 3D-printed model of Vulcan

 

There are various rods and pipes still to be added to the basic 3D-printed model.

 

Seen in isolation, this looks like a well-balanced purposeful engine and, indeed, after conversion to a tank engine, it remained in service for branch-line use until 1868. It’s problem was that it was very lightly built, with a small boiler, in an attempt to meet Brunel’s stringent weight limits (which, in fact, it greatly exceeded).

 

It’s when we look at it against Gooch’s own ‘Fire Fly’ class of just a couple of years later that we see the enormous progress that was made in that short interval. The ‘Fire Fly’ class had the boiler capacity and firebox to cope with express traffic on the newly opened line to Reading and soon afterwards, on 30th June 1841, on the completed length of the GWR between London and Bristol.

 

The difference is very clear when I place my model of ‘Argus’ (Fire Fly class) next to my model of ‘Vulcan’:

 

My models of ‘Vulcan’ and ‘Argus’ head-to-head

 

This has been a journey of exploration for me into the earliest days of the GWR. I hope my readers will enjoy reading about it as much as I have enjoyed making the models

 

Mike