Track ballast is the materials the tracks sit on (in the prototype). A well-ballasted track will make your scene realistic. The detailing will include weathering the track itself, adding rocks, gravel and other materials, so that the track itself blends into the scene.
Before ballasting, test your track so that your trains are running perfectly. A good test is to run five or more cars backward, quickly, around the layout. If you can run around and around the track, no wobbling or derailments, then you are ready to ballast. If not, you need to check your track, and the wheels on your train, and fix any problems. Gauges can be purchased to make track and wheel checking simpler.
Weather ties and rails using a wash of paint. Burnt umber color is a good start, wiping the rail tops off immediately. Keep the paint out of switches and linkages.
Ballast track when you have completed all the other scenery. Ballast should flow over the right-of-way to naturally blend into the surroundings. Use real stone ballast for the best look. You can test for this by dropping a bit into some water – if any of it floats, it’s organic, and won’t look correct. Real stone ballast stays put.
Use your stone size to be one size smaller than you think you need – if you have an HO layout, us N-scale ballast.
You’ll want to bond your ballast, using white glue diluted with water. You can add a few drops of dishwashing solution as a wetting agent, to help it flow. Keep ballast away from moving parts of turnouts. Keep the ballast down between the rails, not on top!
Weather ballast with a thin wash of earth tone paint.