Since I'm working on the engine servicing pits, I decided cinders would be appropriate here, and if I want to add additional material (dirt, etc.) then I can add layers. This is actually two layers already. One section I did by spreading Aleene's Tacky Glue and adding the cinders to that. It works very well, but is impractical since I can't use that method to ballast track. So I wet the board with Future, then added the cinders, and vacuumed when dry. That removed a bit too much, so I added a second layer and that's working much better.
You can see the difference between the cinders that were glued with Aleene's (between the top two pits) and Future (the rest of the board). I still have weathering and a few additional details to add to these, then I need to build the old foundation and, if I have the materials, the storage building that's still standing just beside these.
Anyway, I'm very happy with the results, and it's quite repeatable which is really what I'm looking for. The cinders themselves are a mix of the actual cinders from Essex, but they turned out to be basically light gray ash, so I also sifted some of the coal dust from the next pile over. I really like the color, but as I noted, was having trouble with it separating.
I'm going to try to finish this scene before the New England Proto Meet, since it's on a separate board and I can bring it to display.