Warren and Cid,
Vic is right with his warning about magnetic particles. Black sand for 'sand-arters' could contain ferrous oxide which can raise havoc with our motors.
For industry yards and the area around the engine house I used very fine grained sand, I bought in a pet shop. They called it 'Bird Sand' because it was used to cover the floor of birdcages. It is almost white in color and has many other uses in landscaping, too!
In my industrial yard I added black watercolor to the wet-water/glue mixture, then I repainted unsatisfactory spots with brown black watercolors. So I got that dirty, oil-soaked look.
When filling in the sand between the rails just be sure to completely cover the ties, but leave room enough for the wheel flanges. As the picture shows, all you finally see are the railheads.
BTW, my layout was N scale, so in H0 scale the ground structure should turn out even finer than in my pic.
Ron