Weathering your toy trains is a creative way to depict realistic landscapes. Begin your project by looking up images of old trains on the Internet or in books. Take note of how rust and grime build up on the trains. Observe where black dirt has built up in the recessed areas of the trains and where shiny metal still protrudes on railings. Each model train car can be its own unique work of art with a little planning and the correct materials. This process takes practice. Be patient, and practice first on cheaper model cars.