I was thinking that, and I can also add a pin with a small loop at the top end to go down it and also add a drop loop, so that I can couple as well to other vehicles which have a protruding point on their buffer or somewhere else. The good thing about making drop loops is that they do couple to a number of different coupling types though some may need adapting with some sort of protruding pin or point.
Here is a photo showing coupled waggons. The two skip waggons of various sizes (Rusty looking one is new to my collection) are not coupled but do have pins sticking up, so all I have to do is make little ovals of wire to couple them. Easy to do. I may either have little chains fastened somewhere to these ovals so they don't go astray (When I make them) or I will design and make some sort of drop loop. I took the photo by a Gnomy truck as a size reference as someone I know has one, and wanted to know the size that 7mm scale narrow gauge is (0-16.5).
Waggons 06 and 08 have real rusty bodies, as where I was living things rusted fast, so all I had to do is leave old tin outside for a few months (A week or two if I rubbed salt into it) and it would go rusty. The only downside is rust holes do eventually appear, but I can always make another body when they do! They run on old Triang bogies with modern wheels slid onto the Triang axles, not forgetting to use pieces of plastic drinks straw to use as spacers to stop the wheels sliding sideways and hitting the frames.
