Hi Jon,
I'm very much in favor of using CAD and I definitely want to encourage you to post what you discover.
It would be fantastic if there was a world-wide cadre of people doing CAD designs for Locosts and other neat transportation devices. Imagine if you could look at a build log and see a great solution and that builder could send you a CAD file you could immediately use or send to a local shop to have it made (assuming you didn't have the tools and skills yourself).
Some folks think that process is underway now with the use of the free version of Google SketchUp (
http://www.sketchup.com/intl/en/product/gsu.html). I'll have to say right up front that I'm not a fan of sketchUp for engineering design.
I have a couple of questions for you:
1) What does CAD mean to you: 2D or 3D?
2) Which free programs did you find and can you list them and their source (website, shareware)?
3) Do any of the 5 you've found import and/or export in any industry-standard kind of format like STEP, IGES, or STL?
Regards,
Lonnie