Static Grass

Just before lockdown, I took home one of the club model railway boards that I had been working on. As the club was to be closed, I also took a selection of club materials to finish the scenery in all the spare time I (didn’t) have.
The first job was to add some buildings and walls, and tidy up the grassed bank and steps. I also used the club Static Grass Applicator to add some “grass” behind the road:

I also added a couple of fences:

The next job was to apply “grass” to the rest of the board. I was unconvinced that the club applicator was working properly, and another one that I borrowed didn’t seem to be much better. These work by generating a very high voltage, and using static electricity to attract the “grass” onto a layer of glue, the idea being that most of it sticks up rather than laying flat.

In the end, I tried adding  a metal tea strainer to the club applicator – this looks rather unprofessional, but worked much better:

I then used this to make some grass “clumps”. First off, a couple of bits of wood with holes in are clamped to an aluminium sheet, then small dobs of PVA glue added in each hole with the cocktail stick:

The grass is loaded into the tea strainer and the electricity switched on:

When the strainer is shaken, the fibres are attracted to the metal sheet and the holes gradually filled up. The fibres also go everywhere else of course, so need to be swept up to be reused:

Once the excess is shaken off, you can see the filled holes:

This is repeated a few times with different ‘grass’, then the wood frames are carefully removed, leaving the clumps on the metal sheet:

And in close up:

Once the glue has dried, these can be popped off the sheet and glued into place on the layout.

Part 2

I then decided to buy my own Static Grass Applicator so that I could use it on my layout. I found a ‘tea strainer’ sort for sale, but it didn’t seem to work very well. A bit of research revealed that it was a modified electric fly swatter, and didn’t produce nearly enough voltage to move the fibres. With help from a colleague, I rebuilt the circuitry inside to double the voltage output to -3.4KV, and it now works far better than the club one!

The cover on the tea strainer is good as it stops the fibres flying out of the top of the tea strainer:

Now all the bits are in place, all I need to do is finish the club layout board!


Coal Post

I’m helping our model railway club build a layout that is set near to us in Swanley. In the real world, there is a Coal Post at the side of the line between Swanley and St Mary Cray station:

I thought it would be worth having one on our layout, so measured some photos and 3D designed one:

Unfortunately, this didn’t print terribly well on my 3D printer:

A friend of mine has a much better 3D printer that prints using resin, and this gave a much better result:

And this is what it would look like on one of the model railway boards:

It will need painting and weathering, but I’ll leave that to the experts in the club.

Controller Holders

Now I’m a bit more familiar with the 3D design and printing process, I designed a holder for the handheld controllers used on the railway:

This is a holder fitted to the side of the layout:

And a second holder, with the controller in place:

I then designed and 3D printed a second holder for the small control panel at the ‘country’ end of the layout:

I was pleased with this one as I got the design and size right first time!


Automated Level Crossing Prototype

One of my background tasks for the last year or two has been building an Automated Level Crossing to go by the halt. There are various designs around, but many are very complicated and often too deep to fit under the baseboard.

This shows the gates on the current prototype – it operation, they all move so that they close either the tracks or the road:

Underneath, it’s a bit more complicated:
Each gate is mechanically connected to a servo using a pair of gear wheels. The servos have small motors that are driven by the electronics in the middle.

The end position of each gate can be independently set using the small push buttons on the electronics board. The speed of movement can also be programmed.

Originally, this used standard servo arms to connect the servos to the gates, but these didn’t move the gates to the exact position reliably.

I spent a while looking for better solutions, then looked at various designs of gear wheels on the internet, found something the right size and then printed them on the 3D printer:

They are a bit rough, but serve the purpose and seem to work well.

Now I’ve got the mechanics right, I need to find some better level crossing gates before adding it to the layout.