Thomas Modification ideas: assistance needed

I think painting is a bad idea, @ucwepn tried painting his jinty wheels black but as it ran round the track the edge that rubs against the track wears off, it may be better selecting some lighter coloured wheels and dying them,

There isn’t much on this forum, but on the internet as a whole there is a wealth of knowledge on plastic dyeing, I know a lot of people who dye radio control car parts (wheels) the die permeates the plastic and makes colours the plastic rather than covering it, it means it won’t rub off,

I’ve not tried it myself but I think it would be the best option for wheels,