David Joy's 'Jenny'
@Compound2632provided the answer to my question “Where next, I wonder?” at the end of my previous post about Dewrance’s ‘Bird’ class for the Liverpool and Manchester Railway.
‘Jenny Lind’ took British locomotive design into what might be termed the ‘modern age’ partly by abandoning one of the early Victorian ‘sacred cows’ that a low centre of gravity was essential and also by recognising that increasing the boiler pressure was an important step towards greater power and fuel economy.
There is another link, in that ‘Lion’, which I referred to in my previous post, was built by Todd, Kitson & Laird. E.B.Wilson worked for that company for a short time before founding his own company, with David Joy as manager of the drawing office. In that capacity, Joy played a major part in the development of the ‘Jenny Lind’ locomotive.
After modelling various obscure prototypes, I felt I was returning to the mainstream, with a prototype which has received attention from many other modellers. For example, there is a fine example on @5&9Models'Blog .
As usual, my aim was to create a model that I could then place in context with other earlier and later designs.
Creating a 3D Model of ‘Jenny Lind’
I have a fairly standard routine now for creating engine models, starting by importing a drawing into ‘Fusion’ as a ‘canvas’. In this case, I used a 3-view drawing published in ‘The Engineer’ (6th March 1896, p.246.)
Drawings of Jenny Lind locomotive, from ‘The Engineer’
I found a rather beautiful engraving, also in ‘The Engineer’ (Jan. 10th 1896, p.36)), which helped with the details:
'Jenny Lind' Engraving
I extruded the various parts separately – boiler, firebox, smokebox, etc. before bringing them together as a 3D model in ‘Fusion’. I keep all the parts as separate bodies, so that they can easily be modified later, if necessary, and be rendered individually in ‘Fusion’, which helps when re-creating the complex liveries applied to many 19th century locomotives
Modelling the Boiler Fittings
As is the case for almost all my models, there were a few new lessons to be learned. The fluted dome and safety valve cover are typical products of E.B.Wilson & Co. (and later by Manning, Wardle & Co.)
I already had a fluted barrel for the dome, which I had produced for my model of ‘Aeolus’, so could import that into my current model, but the tapered and fluted safety valve cover was a new challenge. The method I devised was to first draw a rectangle corresponding to the width of one of the grooves in the sides of the cover’. I then tilted the rectangle with the ‘move’ tool so that it corresponded to the inclination of the side of the cover and used the ‘push-pull’ tool to cut a single groove into the cover. After that, I could use the ‘pattern on path’ tool to create a circular pattern from this single ‘feature’ This process is shown below:
Steps in creating fluted safety valve cover
The riveted outside frames and wheels were created by my usual methods, while the side sheets to the footplate were copied from my model of the 'Bird' class. Since ‘Jenny’ is a more familiar prototype then many of my recent models and a very ‘pretty’ engine, I decided to create more of the minor parts than I often do.
Modelling the water feed system
The sandboxes were a simple extrusion from the profile but the feed pumps and injectors presented a greater challenge. I have not gone for a ‘hi-fi’ representation but something that I feel would be appropriate if printed at 4mm/ft scale.
I built up these items from a collection of smaller components that I then brought together into a 3D model. For the injector valves on the sides of the boiler, I created the parts shown below using ‘revolve’ and ‘extrude’ tools, as appropriate, from the drawings:
Feed water injector
Similarly, I created the water pump from the following individual parts:
Feed water pump
I then used the ‘combine’ tool to assemble these two items and, finally, linked them all together by means of the ‘pipe’ tool in ‘Fusion’, as shown below:
3D-model of feed water ‘plumbing’
A few other detailing parts, such as the Salter spring and whistle, came from other models.
‘Rendering’ my model in ‘Fusion’
With all these parts completed and placed on the main model, I think my model looks rather striking in the livery that I copied from an illustration on the Getty Images website
Two views of my model of ‘Jenny Lind’
Comparisons
As I stated at the outset, my aim was to create a model that I could place in context with other designs. I believe that this can be very informative, as individual illustrations often fail to show differences in scale.
A good example is the comparison between my previous post on the L&M ‘Bird’ Class which first appeared in 1841. At first glance, they look fairly similar … until I put them side by side:
Compare ‘Ostrich’ and ‘Jenny’
Moving forward in time, the ‘Jennys’ first appeared in 1847. In 1866, Armstrong introduced his ‘Sir Daniel’ class on the GWR, which I have also modelled . The comparison of these two is shown below:
Compare ‘Jenny’ and ‘Sir Daniel’
Through the intervening years, the basic layout of the engines has not changed but the early Victorian obsession with low centre of gravity has gone, so that a larger diameter boiler can still fit between the wheels and the firebox can be expanded. The pattern set by the ‘Jenny’ was to continue through most of the 19th century, until the mould was finally broken by moving the cylinders outside, so that these could also expand.
As a note to myself, the increasing open-ness below the boiler means that I must do more to fill in the ‘motion’.
Mike
Edited by MikeOxon
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