Woodland Scenics C1281 Extra Coarse Gray Talus

21.6 in3 (353 cm3) Generally, what is the difference between Ballast and Talus? Ballast is placed along the railroad track to model actual ballast that holds track in place. Talus is used to model rock debris under rock outcroppings, rocky hillsides or embankments. What is the best way to model sand? Place fine grade Talus in a plastic bag and seal it. On a safe surface, tap Talus with a hammer until desired consistency is achieved. It can also be colored with Earth Colors Liquid Pigment to achieve the desired color of sand.