How to Design the Interior of Model Railway Structures

Cut polystyrene blocks to size; choose blocks that are about 2 inches by 2 inches and 6 inches long, as these will be easy to work with. Build these up in a pyramid formation that approximates the size of the hill you want to build; each layer should be smaller than the one below it.

Glue the pieces together once you̵7;re satisfied with the general size and shape and glue to the base of the layout. Allow time for the glue to dry. Cut the edges of the block with the knife to create the general sweep of the structure. Drape dry modeling rock ̵1; fabric impregnated with plaster ̵1; over the structure; this will offer a rough idea of how it will look when you̵7;ve finished. Make any changes needed, cutting more from the edges of the polystyrene with the craft knife.

Brush off small pieces of polystyrene that cling to the basic structure. Fill between the layers of the polystyrene blocks with spackle, smoothing and spreading with the spackling knife. Create as natural a slope and sweep as possible, but don̵7;t worry about being exact. Continue across the whole structure and leave to dry. Cover once more with dry modeling rock to judge the final look. Add more spackling as necessary to alter the look of the structure.

File the edges with a wood rasp to create a more natural look, working on both the polystyrene and the spackling. Go slowly and keep putting the modeling rock on the surface to see the final look. Continue until you̵7;re satisfied.

Brush the area to remove as much of the loose polystyrene and spackle as possible, being very gentle. Vacuum the structure and surrounding area, using the smallest attachment on the machine, until everything is clean.

Cut a layer of modeling rock so it̵7;s a little larger than that structure. Soak in water for five minutes then lay over the structure, patting down to give an exact fit. Leave to dry and then cut off the excess with a craft knife. Repeat with a second layer of modeling rock.