I reached something of an impasse at the end of my previous entry in this blog. Lots of problems to be addressed but no clear routes to solutions.
Possibly the most striking feature of the ‘Waverley’ class 4-4-0s was their wholly-exposed coupled driving wheels. I therefore felt strongly that this was an aspect that my model had to capture. Unfortunately, there seems to be no commercial source of 24 spoke, 7 foot-diameter driving wheels and, while I fantasised a little about building my own, I quickly realised that it was beyond my skills and the tools that I have available.
Then, looking at my Tri-ang ‘Lord of the Isles’ model, I suddenly realised that its driving wheels had the requisite 24 spokes! For once, however, Tri-ang had not made their driving wheels grossly under-size but they did have massive tyres and flanges, which offered scope for turning them down to somewhere near 7 feet. So, the next step was to buy some spare wheels (Hornby X275/X276) for only £1.90 a pair.
Not having a lathe, I mounted the wheels onto a spindle and fitted them in the chuck of my stand-mounted Dremel drill. I then used a variety of tools, including a diamond slitting disk fitted in another mini-drill, and an assortment of files, to reduce the size of the massive flanges. Even with a minimal flange, the overall diameter (including flanges) was still 30 mm, so I decided to remove the flanges altogether from the leading pair of drivers. With a long, rigid wheelbase, I felt that this would give the locomotive some chance of negotiating curves.
Another important reason for reducing the overall wheel diameter is that the coupled wheels are mounted very close together, so any excess size increases the minimum possible wheelbase, which I felt would be even more obvious than over-size wheels. After completely removing one set of flanges, I found that I could use a wheelbase of 31 mm, which I was prepared to accept as close enough in scale to the prototype’s 7’ 5”.
Nevertheless, this compromise meant that I had to redesign the inside frames, so as to provide extra clearance between the driving wheels. Since I had drawn the original frames with the Silhouette Studio software, it was easy to modify the details, without having to do a complete re-design. I feel that the revised frames do not ‘look’ appreciably different from the original frames shown in my previous post.
I ‘tacked’ the frames temporarily to the boiler assembly by means of Uhu adhesive and then checked that all the wheels could be fitted, without fouling each other. Now my model was beginning to look like a Broad Gauge locomotive.
I assessed the appearance from different angles and believe that it has captured much of the ‘character’ of the prototype, even though it is not a strictly accurate model
Finally, I set the part-finished model head-to-head with my model of the ‘Rover’ class 4-2-2. This comparison revealed that I need to make further adjustments to the boiler pitch and the frame height but, since nothing is fixed as yet, this will be easy to rectify.
Of course, I’m not completely out of the woods, yet. There is still the matter of those bicycle-like splashers, with their brass facings.
Even so, I am very pleased to have reached the current stage, which at one time seemed an impossible task for me. I find it rather inspiring to see this mid-19th century locomotive coming to reality on my work bench.