Drawing your layout - manual and CAD solutions
By Douglas J. Hughes
Last Update: November 6, 1997
There are at least four good reasons to prepare a scale track plan and design drawing for your dream layout:
A scale drawing is a great check method to confirm that everything will fit.
Your memory can play tricks on you. The drawing is there to remind you of your earlier plans.
It'll save about a thousand words when you try to describe your layout to colleagues.
It will serve as a record for the changes you incorporate as you build, but only if you change the drawing as applicable.
Before starting your drawing, carefully study the references by John Armstrong and the NMRA Data Sheets and Recommended Practices relating to track work curves and switches. Understand Armstrong's
design by squares and apply it.
SIZE THE LAND GRANT
The early US railroads were given staggering amounts of land by the US Government through which to build. They would then sell off the land to help finance construction. We aren't that lucky.
We have those small spare bedrooms, attic rooms with tough access or weird ceilings, poorly lighted and damp basements, or garages that are too hot in the summer and too cold in the winter.
Maximizing the size of your land grant is where the most creativity is called for by the layout designer/builder. Armstrong writes a lot on the subject. Read his writings on "political boundaries"
before proceeding.
Once the space is found, measure it and its peculiarities (drain pipes, electrical panels, doors - hopefully outward swinging, overhead obstructions, etc.). Spend some time drawing the space to
scale. Construct a 3-D model of the space if desired. Start a three-ring binder for your design and put this drawing as page 1.
DESIGN BY SQUARES
Armstrong also writes a lot about conceptualizing your space in terms of the number of squares it contains. The size of the square is a function of your scale and minimum radius. A fairly common
example square size has 26" sides for 22" minimum radius and 2" track spacings for HO scale. Study Armstrong. Don't doubt for a minute that the method will work.
CREATIVE DOODLING
Once you've measured your land grant and determined the dimensions of your "Armstrong Square," start carrying available space drawing copies with you so that you can doodle main line track
arrangements as ideas hit you. It is convenient to use quadruled paper with the 1/4" spacings. Available-space diagrams can then be drawn using a scale so that each square has 1/2" sides. For some of
the smaller spaces, four such drawings will fit a single sheet of 8-1/2 X 11" paper. For this phase of layout design, the complex drafting tools consist of a pencil, credit card, and nickel.
You'll find that eventually several of your "creative doodles" look good enough to be developed into a track plan. It will then be time to create a scale drawing.
DRAFTING METHODS
Use either manual drafting methods or computer-aided drafting (CAD) methods. The initial drawing time will be about the same with either method. CAD can save a bit of time by allowing the drawing of
transition curves and switches once for reuse where they must be individually drawn with manual drafting. Use whichever method is more comfortable. Often transition curves and switch drawing
templates can be fashioned from styrene once you've picked a scale. John Armstrong uses a lot of templates for his manual drawings.
MANUAL DRAFTING
Choose the largest manual drafting scale that will allow your paper to fit your drawing board. Tools required include:
Lots of light
Good erasable bond drafting paper
Drawing board or table
T square
30- and 45-degree right triangles
Engineer and architect scales
Calculator (or a slide rule for you gray beards)
Long-base-line compass
Protractor
French curves
Eraser and eraser shield
Drafting or masking tape
Hard lead pencils and pencil pointer
Inking pens (optional)
Key dimensions to remember are your land grant (room) size, minimum curve radius, minimum switch number (5 or greater is highly recommended), minimum aisle widths (a function of the girth of yourself
and your colleagues - 3 feet is recommended), and your arm reach (typically 28-35"). Layout height preferences will also impact a lot of design decisions relating to scenery vertical heights. Decide
if you want to watch your trains from above (helicopter view) or closer to eye level (railfan view). Also decide if you will be operating from standing or seated positions. Refer to Section D-6
CONTROL SYSTEMS <http://www.vetmed.auburn.edu/~smithbf/BFSpages/LDSIGprimer/Controls.html> for more information concerning this important subject. Draw with a light pencil line because you're
going to be doing a lot of erasing. Draw your most complex track arrangements first and fit the rest of the track plan to them. These will most likely be in room corners and yards along long
walls.
Try to avoid long stretches of tangent (straight) track that parallel either the wall or aisle. Tangent track at a slight angle to the walls and aisles will make the scenery look better. Some
modelers prefer track parallel to the walls and aisles (such as David Barrow), so don't think of this suggestion as a die-hard rule.
Don't be afraid to change the drawing. Trial changes may be drawn to the same scale on another sheet and then overlaid on the main drawing for a sanity check.
CAD Modelers are becoming much more computer literate. CAD makes a lot of sense, especially for making changes to a drawing. The technology is quite mature, however most CAD software has a very steep
and long learning curve. A recommendation is to just pick a CAD software package and take the time to learn it.
Software can be conveniently divided into the following three categories:
Graphics Software
Most graphics packages will allow drawing of the basic shapes needed for track plan drawings - circles, straights, angles, etc. They are usually inexpensive, and most computers come with at least one
graphics package pre- installed. Packages such as Corel Draw, Freelance, WP Draw, Canvass, etc. are well known and usable.
Model Railroad Specific CAD
Several commercial and freeware/shareware products are available. The commercial products are advertised in the hobby press. Any that have remained in the marketplace for a year or more are good.
Three such products (CADRail, Design Your Own Railroad, and PC-Rail) were reviewed in the April 1994 issue of Railroad Model Craftsman and the June 1994 issue of Model Railroader magazines. One of
the three (PC-Rail) is no longer advertised, however this author has used it for a particular design problem. The PC-Rail software had a few problems with non-NMRA switch angles, editing problems,
etc. but was easy to learn.
CADRail and a product from Atlas, called Right Track, have active internet on-line support groups and chat lists. Atlas also supplies a demonstration of the software through their company web site.
CADRail has a very large following and was written by a model railroader.
The model railroad internet newsgroup has recent postings concerning freeware/shareware offerings. One with repeated postings is called WINRAIL, a product from Germany. Users like it.
Pure CAD
There are a number of software packages for general CAD use. The top-of-the-line has remained AutoCAD for the past few years in any magazine review of the various packages. It is very expensive, but
there are affordable options. A striped-down and lower-cost version is called AutoCAD LT. This author purchased a student version of AutoCAD at a local college bookstore at a very reasonable price.
It was not the latest release, but entirely adequate. It even allows three-dimensional drawings. At least one model railroader works at Autodesk, the maker of AutoCAD, and has been available for
e-mail support for track planning advice.
Other pure CAD packages worth consideration at prices well under $100.00 are Softkey's KeyCAD and IMSI's TurboCAD.
The beauty of these CAD packages are edits. Some of the key edit and drawing features to look for in a CAD package include:
Fillet (change angled lines to curves)
Trim
Extend
Polylines (lines with special features)
Draw Offset (to arrive at both rails on either side of the track centerline)
Blocks (save drawing elements for later reuse)
Layers (sections of the drawing that can be turned off, different colors, etc)
Erase
Move
Copy
Mirror