Now, the thought of colour coding the wiring did appeal to me and, looking through Jaycar's list of wires and cables, I came across this: https://www.jaycar.com.au/light-duty-hook-up-wire-pack-8-colours/p/WH3009 (each of the colours is, of course, also available separately). I was to go to the nearest Jaycar shop over the next few days to get some, together with a few other bits and pieces until I noticed one thing. When I looked at the specifications, it said that the cables were rated at 0.6amp. Hornby Dublo 3-rail locomotives, when they were new, were said by Meccano Ltd to draw a maximum current of 0.65amp. Added to this is the possibility that the odd locomotive or so might draw slightly more, due to age related wear and tear, although I have overhauled most of them, so this may not be much of a problem.
Although I do understand the basics of electrifying a model railway, my understanding of electrics is somewhat limited, so I was hoping that someone who knows more about the subject than myself could advise me as to the best wire to use and where to get it. Would I be asking for trouble if I wired the layout using cables rated at 0.6amp when my locomotives could draw a maximum current of 0.65amp? It seems to me that maybe I should be using wire rated at 1amp or thereabouts, but I don't really know. Jaycar do have heavier duty cables but, unless I missed something, they are rated at 7.5amp and upwards.
I mentioned Jaycar only because they are the only place in Sydney I know of that sells this sort of thing - if there is somewhere else I should be looking at as well, I would like to know of it.