Benchwork plans can be designed for model train layouts of any size to fit a room or any other area once the available space is defined. For this discussion we will assume a space of 9' x 11' is available for an HO scale train layout. The benchwork plan can be converted to any other scale with the conversion factors found in the scale and gauge page. Once the space is found, the next step is to select a track plan. This can be done using a custom design of your own or selecting one from the large number which is available in books, magazines, or on-line. The track plan shown here is a custom design with the following specifications:
Scale: HO (1:87) Size: 9 x 11 feet Minimum Radius: 18" Minimum Turnout: no. 5 Maximum Grade: 2 percent Size of Squares: 12"
The values above are selected only for the purpose of this example. They can be changed to fit your own requirements. The selected track plan is illustrated below.
Make several copies of the track plan and draw in 12" squares as shown on the illustration above. These extra copies can be used for notes and drawn in revisions. The squares show only the area of the track layout and not necessarily the total room area. On one copy draw in the preliminary location of the joists which will support the track roadbed (shown below in red). Remember that joist location is selected only as a first guess and will likely be relocated when actual benchwork construction is started.
The 12" grid lines will aid in the approximate location of the joists and other parts of the benchwork structure. Once the location of the support joists are drawn in, position the L-girders(blue) and leg assemblies (green) as shown below.
Note: Grid lines and track plan are omitted for clarity.
The structure now has the main components of L-girders, leg assemblies, and joists. Note the additional 3 joists provided by the leg assemblies. When built the structure should look something like this:
The track plan shows elevations from 42" to 45" and the maximum grade is 2%. A 2% grade means a rise of 2" in 100". Since 8' = 96", a rise of 1" in 8' is considered a 2% grade. The base track level is at 42" above the floor as noted on this layout. The next step will be to draw risers to support the track roadbed. Begin by sketching the risers at the locations shown on the track plan at 42", 43", 44" and 45". As shown on our example, the base roadbed level of 42" is the top of the joists. The grade rises to 45" then decreases to 42" at the second small yard location.
Finally, sketch in the track roadbed:
This example describes one way to approach designing benchwork plans. For larger around the wall layouts it is important to also plan for aisles and access. Aisle width should be about 3' for comfort but in a tight space situation can be 30". Most benchwork plans, including the one above, can be expanded or modified to fit the available space. The important point to remember is that a little bit of pre-planning and even a rough sketch with measurements will avoid a lot of headaches when construction begins.