Since the subject of ballasting came up here, I thought I'd give folks here the privilege of hearing my expert take on this subject (not!).
Forgive me if you've heard this from me here before. I think I have a superior way to do ballasting, although it does take a lot longer.
The commonly-accepted way to apply ballast is to put the ballast in place, then glue it in place by basically drenching it in dilute glue. I don't like this; it does work to secure the ballast, but it leaves it covered with, well, a layer of glue.
What I do is to apply glue (somewhat diluted) to the area I want to ballast, the sides of the track and between the ties. Then I dump ballast over these areas, completely covering them. After the glue dries, I then remove the ballast. How do you do that? you ask. Glad to answer: I vacuum them up, using an inline filter of my own design connected to the vacuum hose, with a piece of nylon hoisery inside to trap the ballast.
It usually takes at least two, sometimes more, applications this way to get sufficient ballast down. It does take longer and is more work. But the surface of the ballast is pristine. No worries about gloppy glue showing.
Try it; you might like it.