Jan 09, 2020 · For my river bed I would glue it down before adding my Mod Podge(water) as far a ballast for my track I did not want sand and saw that some use crushed that's an want to keep things as light as did not know that that the ballast used by Woodland scenics was crushed walnuts but the price is kind of it as ballast I was going to spread glue then ...