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  • Modeling Streets and Roads Part 1 - Dirt

    by Doug Geiger, MMR

    Photos by the author

    Characteristics of a dirt road include little drainage profile, vegetation within the tire tracks, and some ruts.
    Model Railroading - May 2002 - Page 33

    Although most layouts include some form of streets or roads, few seem realistic or believable. Many are too narrow...or the curves are too sharp...or the coloring just isn't right. This series of articles will attempt to show the modeler how to make more realistic roadways. It will concentrate on roads, but many of the techniques shown will work equally well for city streets.

    The series will concentrate on dirt, gravel, asphalt and concrete roadways. By using the step-by-step how-to photographs, you can easily duplicate these techniques. Eight road construction methods are illustrated. Some commercial materials are involved, but most are readily available. Although the methods shown were developed for HO-scale layouts, most of the techniques can be applied to other scales. Some are even better suited to other scales.

    Since road signage (both on freestanding signs and on the pavement) has changed considerably over the years, this article will not address those markings. They are very era-dependent. For example, do you remember when STOP signs were painted yellow and not red? Road construction, however, has not changed much since roads were first developed for the automobile, so the eight techniques should be era-independent. Only lane widths have changed over the years.

    Part 1 will concentrate on preparation of the site, which can be applied to any road surface. It will also cover the building of a dirt road. Part 2 will cover two methods for making a gravel road. Parts 3A and B will concentrate on two ways to develop an asphalt highway. The three sections of Part 4 (A, B and C) will show three techniques to make a concrete roadway.

    Although some of the examples show grade crossings, this series will not address them explicitly. Where appropriate, prototype photos are included to demonstrate color and texture of certain roadway types. Each section is independent of the other techniques, but one can always combine methods for variety (like a gravel shoulder on a concrete highway).

    Begin any roadway by planning out its path. The main dirt road is sized for a 12 lane (for two cars to pass) and the farm access road across the tracks is narrower to accommodate just one automobile.
    Model Railroading - May 2002 - Page 34

    Site Preparation

    The best way to model streets and roads is to observe real highways as you drive along them. Note the colors and pavement profiles. Take photographs to aid in your modeling. Note also the drainage ditches and mix of materials used. For example, by observing some roads around our hometown, concrete two-lane roads are not as common as asphalt two-lane roads. However, many four-lane roads are concrete. Also, roads are considerably grayer than most modelers make them. The real ones tend to be much wider, too. And there are many wooden grade crossings still in place on many secondary roads. It was also noted that most gravel roads were a combination of gravel and dirt.

    Lane width for modern highways (post mid-1950s) has been 12', with 8' shoulders (if applicable). Of course, there are always exceptions, but anything narrower can appear toy-like. Before then, lane width was 10' and shoulders were not common on many highways. Most prototype roads are raised in the middle (crowning) to allow water to drain off, but since crowning is only about 3", modeling it is not necessary.

    In planning where your roads should go, try to imagine yourself driving on those roads. Can a large truck with a trailer negotiate the curves? As an example, most grade crossings are done over straight track so try to avoid a highway crossing curved track. Also, most streets are perpendicular to each other, although adding an occasional diagonal street adds variety. Make a note of necessary highway signs as you plan the highway.

    Road planning follows many of the same rules as track planning, e.g., avoid a street or highway paralleling the fascia edge or backdrop. Try to have a road enter a backdrop at an angle or hide that intersection with a hill or some trees to soften the abrupt transition from 3D roadway to 2D backdrop. Also, remember to include an access road to your structures. And dont forget parking lots. Plan the streets as you plan for your buildings. Leave enough room for the roads.

    After cutting and staining short pieces of wood to make the grade crossing, glue them directly to the ties with gapfilling cyanoacrylate (CA) glue. Note that the ends of these pieces are beveled to prevent snagging a coupler trip pin.
    Model Railroading - May 2002 - Page 35

    Try to use as big a curve as possible. Like our model railroad tracks, highway curves will generally be way too tight. But just like track, by using easements on a road, the sharpness will appear less. A median strip (concrete or grass) is a mark of a modern highway. However, the subgrade of a road is important for any roadway. It is like the roadbed of our train track. So proper elevation of the road surface above the surrounding terrain is critical for appearance.

    Almost any material can be used for the subgrade. Depending on the roadway method, you can use styrene sheet, foamcore or Homasote. Corrugated cardboard or poster board is only recommended for non-water-based techniques. Or the roadway can be built up using your basic scenery material, like plaster or extruded foam. The idea is to elevate the roadway surface above the nearby scenery.


    Many access roads into farms and low-speed streets still use dirt as the surface material. No material looks as good as real dirt when modeling a dirt road. Use a finely sifted dirt with no clay or mica present. Keep the ruts shallow for a better appearance. Sculptamold, a commercial plaster/ fiber mixture, and latex paint are key ingredients during construction. Cheap acrylic house paint is used to glue the dirt to the roadway surface. The following series of photos illustrate the steps necessary to obtain a goodlooking dirt road. A wooden grade crossing is included in the sample.

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