Shawn Branstetter has developed a very informative blog that describes techniques for modeling the railroad scene. The emphasis is on technique and materials used by by scale plastic modelers. He has mastered many of the newest modeling paints and materials developed in Europe. Companies like AK Interactive, AMMO by Mig and Vallejo have created the kind of stuff that allows you to build realistic models and scenes. Road building is one such tecnique Shawn developed a system using acrylic paste and Hydrocal creating realistic asphalt material. He shows how to do this in his blog.
Here are a few samples of Shawn’s work on track, layout and building material.
Shawn’s blog is worth a look.