Three-D Modelling for Railways

This is a very small model, not much more than a centimeter high, but it turned out well. I was inspired by a phototype that seems to be almost a permanent fixture near where I work. Not sure if it is still useable, but seems in fairly good shape. This is a Ford 2600, which was produced from 1975 to 1981. I had a toy tractor as a kid that I think was one of these - it was blue and Ford and in that timeframe. Here is the model. Probably the most technical part was the tread on the rear wheels, which was done, in part, using geometry nodes to repeat the same mesh so many times round a circle.

 3D Builder is a Microsoft app that I routinely use to correct issues with models. Any STL file exported from Blender is opened in 3D Builder, imported, and then saved in a different folder, whether the model was corrected or not. I would guess at least eight out of every ten models need to be corrected, so this is great. If it finds issues, it will put a pink box round the base of the object, and I ask if I want to import it. The progress will quickly get to about 80%, then stick there for a while. Sometime a long while! But it always gets there in the end. Today I had a model that is different. It has the red box, but rather than a faded, almost pink red, it was a bright red. And when I imported it, it stuck at about 25% for a while, as well as 80%. Though it did get there in the end, I guess in about 15 minutes so not too long. I cannot find much in the way of documentation on 3D Builder. Plenty of tutorials for beginners, but nothing of any depth. As you can see from the image, the

I have recently made some wagon loads, three of them based on wrapping steel into circles, which poses some interesting challenges for the 3d modeller. There is an article about curves here that will serve as a background to the modelling. https://three-d-for-railways.blogspot.com/2024/02/curves.html I would guess that at one time iron and steel was the second big industry for railways (after coal), and it was the ready availability of both coal and iron ore that made Britain so successful in the industrial revolution. An issue with transporting steel is how do you move it? Coal is in lumps, making transport relatively easy. Steel parts can be huge. It appears it was generally transported between sites in coils and in wire bails. I would guess wire bails are used for making items that are that kind of shape, like thinner wire, nails, etc. Steel coils would be unwound to make refrigerators, ships, or whatever. That said, the first item I made is a cable drum. In fact, it is a set of cab

 Around Easter I pre-ordered a mini-heater for my printer, in readiness for the winter. It arrived a couple of weeks ago, and today I fitted it, as the temperature in the garage was 13°C at 8 am this morning. The instructions are rather unclear, but there is a video here: https://www.youtube.com/watch?v=S7o60xKvTeM And it was actually very simple - though easier if you have a friend to hold it while you put the screws in. Here it is in place, and in action. My first heated run is going! ETA: The run, and and a subsequent one, went fine. The temperature - as it reports anyway - was between 25.0 and 26.0 every time I looked at it. Have to wait and see how it copes when the ambient temperature is sub-zero, but looking good!

 If you every write scripts for Blender, it can be useful to know how Blender numbers the vertices, etc. You can get Blender to show you these numbers by first going to Edit - Preferences - Interface, and in the Display section ticking "Developer Extras". Then go into edit mode, and click Mesh Edit Mode Overlaps; this is top right of the viewport - a square with small squares in each corner, the top right one filled. Tick the Indices option. You need to be in Edit mode to see them and only selected will be shown. Note that Blender numbers from zero, which is common in coding. This reveals a rather odd thing about how the faces of cylinders are numbered.  Vertices are simple. Blender numbers vertices by going round the (supposedly) curved side, starting at positive y. and going clockwise to positive x, alternative bottom, top. So the even vertices are all round the bottom face, and the odd on the upper face. Edges are a bit more complicated. It starts with the first face, with

There are a lot of bridges in Glasgow; this is just about a handful on a line that ran out of St Enoch. St Enoch was a large terminus with twenty platforms, situated just east of Glasgow Central. Trains headed  east out of the station, and then either curved sharply to go south over the river, or rather more gently to go northeast, and there was a chord allowing trains to bypass the station, and the tracks are still in place, as far as I know this is still in use. A large loco shed stood in the triangle. St Enoch is on the Glasgow underground (now the "subway"). This is the original entrance. The main station has been levelled, and there is now a shopping centre on the site - St Enock Shopping. Where the loco shed used to stand is now a car park - I parked our hire care there! This was the chord between the two routes, looking northeast. The arches beyond the lattice bridge are used by various businesses of an upmarket nature. The chord joins the line to the northeast just be