Shaping the Terrain.

In this tutorial we will discuss how I create strong, light weight, realistic terrain on my model railroad. These discussions will include the construction of rigid, durable forms for hills and mountains; the creation of rock faces, embankments, and retaining walls; the creation of smooth or textured undulating surfaces for fields, lawns, forests, and so on. There are a lot of methods for doing this, but this is the one I prefer for reasons that I hope will soon become clear. 

Before we begin, let’s think about the real landscape. In the real world, the landscape was there first. Then man altered it to create roads and railways. On the model railroad it is exactly the other way around: that is, the roadbed and track come first and the landscape is built around it. This may seem like an obvious point, but it is important to keep in mind as you begin to design your own landscape. Try to always picture how the land looked before the railroad. Ask your self, “what did the railroad do to traverse this mountain or this valley?” The answer to this questions is most often “cut and fill.” The point is: you don’t always build mountains that conveniently end right at trackside. This is highly unrealistic. Rather you build a mountain that has a narrow cut gouged through it to allow the railroad to travel on grade. The original contour to the land is still obvious to the viewer, and the effect is more interesting and much more realistic. The walls of this cut may be sheer rock, or more gradual earth embankments. They may even include man-made retaining walls. Beyond the cut, the mountain resumes, just as in the real world,. Likewise, to cross a valley you build a raised roadbed supported by fill. Again embankments, rock faces or retaining walls may come into play. Your small creek crosses under this fill in a large culvert or maybe you create a series of low wooden trestles - much more interesting - much more realistic.



To further illustrate these points, here are a few example photos taken on my Altamont and Blue Ridge Railway.

westridge crossing

Notice that the cuts created for roadways are not so extreme as those created for the railway. Cars and trucks can negotiate much steeper grades and much sharper curves, so roadways tend to more closely track the original shape of the terrain than railways do.


Another planning note: It is good idea to avoid running all track parallel to the edge of the bench-work. Just a little angle and/or curve here or there will help dispel the illusion that your track was created to conform to the bench-work.


Now, with these principles in mind, let’s do a little planning. Look at your track plan. Where will there be mountains, tunnels, cuts, fills? Where will it be perfectly flat? Where will the roads and streams run? It is good idea to sketch out a little topo of the entire layout. Then ask yourself how the contour of the land looked before the railroad was built. Is this realistic? Also at this point it is useful to consider if there are areas of the topo that will lie below the level of the bench-top. Do any of these require modifications to the bench-work? Below are before-and-after photos of the East River on my A&BR. Notice how the river bed starts at bench-top level in the back next to the wall and slants down below bench-top level.

river crossing bench


Unless you are modeling the Bonneville Salt Flats, you should not have many large areas that are completely flat. The only large flat areas on the A&BR are for the yard ladders at Altamont Yard and Altamont Terminal. Of course, the towns and cities have lots of flat space, but they are built on a series of small flat homasote steps cut into the rolling terrain to give the illusion of terracing. For example, notice the three tiers of the town of Westridge in the photo below.

westridge 008

Once you are satisfied with your topo and bench-work, go ahead and build your roadbed and lay and wire your track. Build roadbed runners using ¾” plywood and homasote traversing open bench-work and creating even grades where the mountains and rolling terrain will be. Cover the flat areas with ¾” plywood topped with ½” homasote. I’ll not get into detail here regarding the creation of roadbed and the laying of track for that is not the subject of this tutorial.

After the track is complete, the next order of business is to build in the mountains and the rolling terrain. To form a framework, I like to use homasote cutouts fastened together with sheet rock screws to form a grid-like skeleton. (See the photos below.) This is then covered with plastic window screen that is later covered with Sculptamold. (Don’t use metal screen: it can cause electrical problems, and the plastic is much easier to work with all the way around.) This kind of rigid mountain form has many advantages. It is very strong and completely rigid, very light weight, clean, quick, and easy to build, and, to my mind, it affords the modeler more control over the shape and look of the finished product that most other techniques. The shape of the cutouts exactly determine the shape of the terrain, and building-in rigid foam rock faces and plaster-cast rocks and walls and other details is a snap.

Just a note about materials: homasote is wonderful stuff, and it can be used for a lot more than just roadbed. This 1/2” thick “cardboard” wall board is primarily used for sound deadening in wall construction, and is available at many lumber dealers. It comes in 4’ x 8’ sheets and is easy to cut with a handheld jig saw or even with a box knife. It is very strong, and yet it is soft enough to press small nails into it using any metal tool. Likewise, Sculptamold is amazing. It can be mixed thin to cover large smooth areas or mixed thick to be used almost like clay. It is very malleable when wet, easy to shape or carve when half dry, and it can be sanded when completely dry (although I don’t recommend ever sanding or spray painting in the train room once the track is down). It is also very strong and light weight; and a hard shell of this material will add unbending strength and rigidity to your homasote mountain forms. It also takes paint quite well. Lastly I use latex moulds fashioned around Chooch resin tunnel portals and retaining walls to mold plaster-of-paris tunnel portals and retaining walls that are then glued to strategically placed homasote spanners built into the mountain forms. For rock faces I glue in plaster molded rock or use cut out pieces of foam rock cut from a rigid foam 15 x 6-1/2’' Multi-Scale Embankment manufactured by I. S. L. E. Industries, attaching my foam rock forms to spanners in the homasote mountain form using yellow carpenters glue and sheet rock screws. (See photos below.)

As to construction, the photos below should tell the tale. You can build a mountain like this as a standing lift-out module or you can toe it into the wall board of the backdrop and the bracing of the bench-work using sheetrock screws. I like to keep both 1” and 2” sheetrock screws on hand and a box of 9/16 inch  flat head brads for fastening the screen to the homasote forms. I also use yellow carpenter’s glue to add additional rigidity to the homasote joints of the frame.


Note: There are large mountains in all of the corners of the A&BR, and, using this method, I have fashioned several of these as large lift-out modules that can be removed to allow for cleaning and maintenance access to the tracks in the tunnels underneath.


At this point, it is probably a good idea to just walk you through the terrain creation process from bare bench-work to finished terrain working on a small area of the layout. The area I have selected is above the hidden yard on a raised section of bench work that covers the hidden yard and attaches to the angled hinged access hatch above the hidden yard. Below is the bench-work before the addition of the hidden yard cover and hinged hatch.


Below you can see the complete cover and hinged top. The circled new area where we will be working is to be stepped mountain terraces between the city of Altamont and Altamont Terminal. The bare boarded area in front of the selected area will eventually be more of the city, and the white area and bare gray rocks to the left is an incomplete section that I built earlier and plan to marry to the new section. The flat area to the right of the new terrain is for the future Altamont Cathedral. Notice I have painted in the far mountains of the backdrop. (See my tutorial entitled “Marrying the Backdrop to the Layout.”)


Here is the completed area with the hinged top open.


Below you can see a close up of the homasote mountain frame with its screen over-covering, and attached terraces and rock faces. 
Note that roadways are also roughed in at this point. (For paved roads, I use .040 styrene plastic sheet cut to size, laminated with 220 grit sandpaper and spray painted gray.


Now it is time for the Sculptamold. Notice I have not only covered the screen areas, I have also worked thick globs of the stuff in and around the roughed-in rock face, to tie everything together and to cover the screw heads. You can also see that I have carved some transitional rock forms into the Sculptamold and scribed them with lateral lines to simulate the strata. I have also added some more layers of nearer distant mountains in the form of foliage-textured .040 styrene plastic cuts outs. (See my Tutorial entieled “Marrying the Backdrop to the Layout.”)


Now let’s rough-in a base coat of paint. I use flat latex wall paint: a medium grey for the basic color of the rock and a red-brown earth color for the Southern Appalachian earth. You might want different rock and earth colors depending on the area your are modeling, but remember, this is only the base, and a lot more coloring and darkening and texturing will come later, so the exact color here is not really too critical. It is a good idea to mix and keep on hand a fairly large amount of your base rock and earth colors to avoid having to match these mixed colors later. 


After the gray on the rocks has completely dried, give the rocks a good coat of black wash to get down in the crevices and darken the whole thing. I like to use black tempera powder mixed with rubbing alcohol. (Don’t use plain water, it has too much surface tension and therefore tends to bead up. Many use a thinned down latex or acrylic paint or even an ink wash. You can choose what works best for you. Don’t worry if you make a mess. Except for the deep cracks, most of the black will be covered over later. Just slop it on. Work fast so you don’t get the gray latex flowing again. If you do that, you will just get darker gray solid color rocks, and you want things to look pretty splotchy at this point.


Now let’s put down our first texturing layer on the earthen areas. I use a mixture of tempera paint powder and plaster of paris sprinkled over the painted red-brown earth sections that have been first sprayed with rubbing alcohol. Warning: the dry paint powder has a tendency to get everywhere and as you later spray over any this, it tends to splatter, so it is good idea to mask off nearby track, structures, and roadways and use a handheld shield to protect rocks and foliage and backdrop when dusting the powder or spraying the liquid etc. This technique is a variation on Linn Westcott's famous "zip texturing" idea popularized in the late 1960s. It is described as follows in Joe Fugate’s masterful “Forum Clinic”

“Be aware that the plaster - tempera paint mix darkens quite a bit when you wet it down, so mix up a batch that looks too light to you, then apply it to a scrap of scenery, wet it down and allow it to dry. Once it's dry, check the color. If it's too dark, add more plaster and try again. If it's too light, add more color and try again. Keep track of your formula so you can repeat it later. Generally, you want somewhere between 2 - 8 parts plaster to color, or perhaps 10 parts plaster if you need a really light "dirt". Keep track of the total parts that are color. For example, the rich brown dirt color below has 3 parts that are color, so 9 parts plaster is really a ratio of 3 parts plaster to 1 part color (9 divided by 3 is 3). For reference, here's some simple formulas I use.

Rich brown dirt:

1 part black

2 parts brown

9 parts plaster (3:1 color to plaster)


Tan dirt:

1 part black

2 parts brown

1 part yellow

16 parts plaster (4:1 color to plaster)


Get yourself a tea strainer, spray wet water (water with a few drops of detergent in it) on the bare brown scenery, and sprinkle some of the plaster-tempera mix onto the scenery. Then mist the plaster mix from above lightly with more water from a pump spray bottle. In a couple of hours, the plaster should be dry and set up. If it's still loose, spray it again.


If I want something that looks muddy, I'll soak the plaster good. Or if I want a more dusty look, I'll take it easy with the water.”


After everything is dry, you can use your vacuum to get up any loose powder. You may need to touch up a few spots here and there at this point, but this is easy – just few pinches of the plaster paint powder and few little shots of the alcohol spray.

PS. To make my red/brown mix, I use Joe’s rich brown dirt recipe and add small amounts (perhaps ½ a part each?) of yellow and red until I get what I want.

Note: the contrasting dark and light color soil in the photo is due to the fact that the sculptamold on the left was done much earlier and was complexly dry when I put on the zip texturing, while the newly applied sculpatamold, although it appeared to be dry in the larger new section on the right, was still wet enough to absorb the alcohol spray. When this dries for a week or so, the two will match. Anyway, as you will see, the difference in color won’t much matter once the put on the rest of the ground cover.


Let all of this dry for a day or even two, and then dry brush the rocks with white latex paint. Dry brushing is an art that is critical to realistic modeling. Dip a old 1 inch wide brush in thick flat white latex wall paint, rub the excess off the bristles on the lip of the paint can, wipe the bristles with a clean rag, and then work out almost all of remaining the paint by rigorously and forcefully painting swirls on clean dry newspaper. Use several sheets, and work it until it is pretty dry and almost no paint is left in the bristles. Now just touch it to the rock face working very light strokes that touch only the highest projections of rock. Go lightly at first and harder as the brush become dryer and dryer. You should be able to create a feathery white highlighting that makes your rocks come alive. Practice a little and you will get the hang of it. Notice I have also begun to add clump foliage to create a distant forest tree line and to hide the crack between the sections.


Now let’s rough-in the rest of the basic shrubbery around the rocks using several colors of clump foliage held in place with contact cement.


Now some grass and other ground cover. I like to use a very fine ground foam held in place with white glue. First, thin a little white glue with water (about 1 part glue to 2 or 3 parts water). You want this pretty runny so you can dab it on with a soft brush over the zip textured soil without too much disturbing the texture. For all but the finest lawns, don’t cover the “dirt” completely. Leave little patches of earth dry so they will show through later – just little bare a patch here and there for meadows and fields – much large bare spots for forest floor etc. There are many brands and colors of fine ground foam available, and you have to experiment a little to find what works for you. For a meadow, I generally sprinkle on a rough covering of a nice bright spring green, and then dull this down by sprinkling over a lighter and spottier coat of a dull burnt green. Then I add a few patchs of tan or even yellow here and there. For forest floor, a few patches of various greens, some earth colors, and some fine pine needles, and then a few low clumps of under brush and vines etc.


In the final step, I lightly color dirty patches and patches of lichen on the rocks. Using pastel sticks (a light tan, a red-brown, and some light green for the moss) I draw light lines of color on the rock and then rub and smear this evenly over to create small, very light patches of color on the rock face. (See below.) Then I apply some nice “viney” greenery to the rocks using “leaf flakes” or pulled apart stretches of silflor or other stretchy green net-like material held in place with contact cement. It is good idea to get a Scenic Express catalogue. It is full of ideas and illustrations, and from this you can see the dazzling array of products available. Finally I add the trees – usually several different kinds and colors. If you are careful about placement and sizing, you can use trees fashioned from clump foliage right along with the more detailed trees made with “Super Tree” material from Scenic Express. Before you begin "planting" your trees, place any structures on the scene to help you visualized the scale, and then, since we are forcing the perspective in this case, carefully install the sized trees starting with the very small trees along the tree line in the back and working forward to very large trees in the foreground where things are full scale. I generally first temporarily place a few trees of each size around just to make sure that the sizing is creating the proper illusion of distance. You will find that the placement of the larger, near trees is critical to the illusion of distance, so experiment. I general lightly spray paint trees to bring out highlights (a little short of yellow for larger, brighter, near trees - a little shot of  gray to distance the smaller trees in the background).


In the photo below, you can see the entire finished section of the layout with the section that we have been working on in the upper lefthand corner.overview
That concludes my tutorial. Let me know what you think, You can email me using the link on the home page of this site. Check out my other tutorial by hitting the back button below.