Laying track for your model train layout can be one of the most challenging aspects of the hobby. If your track is not laid correctly, then your trains cannot run on them, leaving your layout inoperable. A few simple rules can help you avoid much pain and frustration.
Lay the cork roadbed on the wood or homasote subroadbed. You may actually want to draw a line on the tabletop marking the paths of your tracks. Use an adhesive such as Liquid Nails to cement the cork down to the layout. Make sure that the beveled edges slant diagonally away from each other on the table.
Nail or cement the track down to the roadbed, making sure that the tops of the rails do not get covered with glue. Be especially careful about the moving points on your switch tracks (turnouts). It is imperative that you keep them free of glue, ballast and other debris so that they can move freely and easily. Drill holes for switch machines and switch stands according to the directions on their packages as well.
Carefully pour the ballast down onto the track, using a brush to cover the cork roadbed and distribute the ballast between the ties evenly. Make sure that all of the cork is covered and none of it is showing. Very, very carefully squeeze ballast between the ties on your switches, leaving the tops of the ties clean to facilitate point movement.
Mix glue with water and a few drops of matte medium and squeeze the solution onto your track with an eyedropper. The mixture will seep through the ballast and hold it firm once it dries. You will have to thoroughly clean the tops of all your rails after you do this, and probably scrape the rails and frogs on your switches as well to make sure that they are free of dried glue.