Hester, I live in Australia, which I think gives an advantage when it comes to SPACE: I have a colliery layout in my cellar. All based around a 4m diameter circle of track (because I like to see continuous running), with deliberately-made gradients, viaducts and embankments, which means that my trackwork is, in places, very colliery-like (ie uneven).
S7 in my experience means that you have to be a little more careful with trackwork, and I haven't yet built my first eight-coupled locomotive. However as I am the only S7 modeller in NSW, as far as I know, it's possible to do it without a lot of hands-on help, and I'd NEVER go back to Finescale: it's too difficult to make all the compromises work together.
An 0-4-0+0-4-0 Garratt makes for a very interesting and prototypical locomotive for a colliery layout (see my "avatar"!).
If you have good broadband and ideally an Apple, look at my video of the model Garratt running, on
http://69.195.124.76/~coulshed/australian-family-events/page/2/
You can see the piles of coal, the "screens", etc of the colliery ....
David