When you do some scenery like grass and what not. Static grass shows up really well though 2mm and 4mm will bring your models out far more then the foam. I have been working slowly on a few modulus for my narrow gauge extravaganza. The only one thats done is a section depicting belgrave trestle from australia. very nice work on your engines I have a puffing billy garratt that i have yet to find the chassies for.