A very boring and yet crucial part of a working railroad are the rocks that lay below the tracks. These rocks are called track ballast. The name is borrowed from the rocks that were used to help stabilize ships as they sailed the high seas.
Track ballast serves several functions:
While these functions aren't needed on your model railroad layout, you'll still want to add material that looks like ballast to your tracks so that the look prototypical.
Below are some links to videos demonstrating techniques to add ballast to Kato Unitrack. Adding ballast to your layout tracks requires some patience. The results will help to bring your layout to life!
I hope that you have a "ballast" watching them! ;-)