Hi Fran. That’s very fine work! Depends what the item is. If you are making, for instance, working level crossing gates to be motorised, then making them able to move is important, and may involve some compromise of scale to make it robust. Generally though, the emphasis in a railway model is scale fidelity. This is where physics comes in and some materials such as plastic have limitations - they are simply too fragile when very thin. The sunburst gate you have so beautifully drawn would work best as an etching on brass, which would be thin enough to get the right definition but also strong enough to stand up by itself.