@SteveH that's been in the back of my mind. I know sand doesn't get along with mechanical movement. I was hoping just being a little more aggressive with maintenance would be the ticket. I chewed up gears on an RS3 as a kid by using loose gravel for ballast and not knowing how to glue it down.
The other good news is that locomotives won't cross over the unloader very often in the course of operation. It's a dead end (and 4 foot drop) beyond the unloader. So I think/hope that will make a difference and prevent sand from getting into drivetrains. So far the coal on the table in the picture has been coal I spilled so we'll see.
Lumber is still expensive and I still need to get the walls/ceiling ready for a table to even be built so I have a few months to play around and see how it works out.