To CAD or not to CAD? That is the question when starting a track plan

This week on the yahoogroup Maine-Two-Foot-Modelers-Forum Lee Rainey wrote:  “I strongly recommend a CAD program as a layout design tool.”  The statement made me ask, “Do I strongly recommend CAD for layout design?”

First of all, I use a XTrkCAD for track planning.  So before I make a recommendation, let me share why I use XTrkCAD.


  • It’s Free! – I use XTrkCAD 3.1.4 which is available in the files section of the XTrkCad yahoo group – – You’ll have to join the group to access the files section.  If you try to use it, you’ll have to use the registration instructions in the same folder – “XTrkCad REGISTRATION INSTRUCTIONS.txt”
  • XTrkCAD 3.1.4 runs on all my PC laptops including my old XP system.  Although the help no longer works on Windows7 (I’m told there is a way to get around that).  Newer open source versions exist too.  4.0.3 seems to be available in the same folder in the yahoo group.  I think it supports other OS’s too.  I think the 3.1.4 version was the last production version by Sillub Technologies.  To get started with later versions try the Wiki
  • Easily enforce Minimum Radius – XTrkCAD has a minimum radius for a layout, when set, any radius less than that value is highlighted.  It’s easy to set a value or larger when inserting curves.
  • Tools to create and insert turnouts – XTrkCAD has pre-defined turnouts or the user can create their own.  I created my own for Sn2.  This ensured accuracy.  I even created special turnouts (shorter straight on the end) so that I could insert turnouts that conform to angle but are modified as I’d modify to install in tight locations.  I use these smaller versions often, and this ensures I have proper dimension through the frogs.  On paper designs it’s easy to cheat on turnout dimensions and create an plan that cannot be built.
  • Easements – XTrkCAD supports easements, and they can be automatic on all curves.
  • Smart Connection of Track – XTrkCAD has the ability to connect track in many ways.  It can connect snap track, it can tangentially connect two tracks and cut off the ends on the fly, it can extend turnouts linearly  it can bend the end of a track, it can split track.  All of these are smart because the CAD tool is Model Railroad specific.
  • Concept diagrams (like John Armstrong’s squares) are easy to do.  For example these concepts I did for Gary White’s Sn2 K&DR (Concepts) or my own Dream Sn2 SR&RL layout (Concept #2 or Concept #6)
  • XTrkCAD can connect modules as I did to generate designs for the Sn2 Crew Layouts (Hickory or St. Louis).  A free-mo setup like this requires trial an error to optimize the setup to fit a specific space.
  • XTrkCAD can calculate grades – This is crucial when creating multi-deck layouts and wanting to determine the impact of having level towns vs. graded towns etc…  See this example image of grade chart generated from one of the concepts for my Sn2 SR&RL.
  • It’s for Designing Model Railroads – In my job, I have access to many high end CAD systems with full drafting.  However, I’d never use them to design a model railroad as they are not tuned for that.  Doing the features I mention above would be time consuming if not impossible on these 10-30 thousand Mechanical CAD systems.

Other Features Of Interest

  • Print Full-Size – XTrkCAD can print the layout full size to many sheets of paper that can be laid on benchwork or plywood or other.  I usually do not use such a method (possibly because i’m against wasting the paper).  Instead I transfer visually making tweaks as required.
  • Full-Size Triangulation – XTrkCAD does not support this, but I think 3rd Planit does.  It is possible to fix two points in the room, and 3PI will calculate the distance of any other point from those two.  Having this would make it easier to transfer designs.
  • 3D Scenery – XTrkCAD does not support 3D scenery, but 3PI and other model railroad CAD packages do.  I see 3D in my head and would prefer to build the scenery rather than design it in detail.  I will do 2D scenery, which XTrkCAD does support and I often enhance using Paint or other programs.
  • Structures – It is possible to make footprints of a structure and reuse that in any design.  Some HO structures are already available.  3D structure might be possible, but I’ve not explored that.  I think the other packages such as 3PI support 3D structures
  • 3D Benchwork and Walk Through’s – Like 3D scenery, not supported by XTrkCAD, but 3PI does support (possibly others too).  Again, I’m not that interested in a 3D walk through.


  • I think the points about XTrkCAD above explain the benefits I get from using model railroad track planing software.
  • Additionally, I often do track planning for others.  Thus I can reuse the skills learned to make a pretty plan for someone else.


  • The justification of using CAD to design a model railroad is an individual choice.
  • I do not recommend it for beginners.  The software does not help them figure out what they want (often the greatest problem for a newbie.
  • Success will depend on CAD tool selected and time one is willing to put into learning the tool.  Expect 20-40 hours of learning.  For small layouts, simple layouts, or one-time designs the effort to learn a CAD tool may not be worth it.
  • The more complex the project the more benefit the CAD tool can provide.
  • If you prefer paper and pencil than use it!
  • If you like designing full-size on the layout or on the floor, then do it!
  • If you hate or fight with computers do not use CAD.
  • No matter how much CAD work is done some redesign will occur during construction of the layout.  Each person will have a different threshold on how far to take a design (time/money)
  • Some modelers might be better off getting someone else to help them with the CAD design or even to pay someone else to do the CAD design.  Byron Henderson, Yard Goat, Lance Mindheim all might be provide such services.

For me, CAD has it’s place so I use it (concepts, figuring what will likely fit).  But CAD is not my end all design technique.  I expect final tweaking to occur as I build or after.  I say after, because one may want to make changes after operating the layout.

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2 Responses to To CAD or not to CAD? That is the question when starting a track plan

  1. Harry Downey says:

    Dave, we have been e-mailing back and forth for a bit now and I have seen the designs you have done for Gary as well as the Sn2 Crew. I took 4 years of drafting/mechanical drawing in high school, but that was all pencil and paper. Still usefull, but a design program sounds like the best way to go. I use a computer for work everyday, but am only proficient at what I do. I hesitate at getting and learning a program because, well I’m just not good at it. It seems the time would be better spent. On the other hand, errors such as the correct angle of a turnout can easily creep into a paper plan as can “pinching” a radius. Considering the options, I would go with the simple model train program. Thanks for your over view.

    Harry Downey

  2. Trevor says:

    Hi Dave: Well-argued.
    I have to admit I’m a pencil’n’paper person, but I have trained myself to design with a margin of error – the turnouts I draw tend to consume MORE space than the actual turnouts, and I leave plenty of space between drawn track and benchwork edges so I’ll never end up running a real track off the edge of the world or into a wall. But my designs tend to be really, really simple these days, with plenty of room for error.
    Certainly, for more complex plans and for situations where size really does matter (such as Free-mo modules), CAD is the way to go. Any time I’ve been working on that type of layout I’ve recruited a friend to do the CAD work for me.
    Always thoughtful writing on your blog – keep it up!

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