Steve,
I am using 3DCrafter 3DC, formally called 3DCanvas. There are three programs commonly used (Train Sim Modeler, 3DCrafter, and G Max) and like everything else, you will hear all kinds of arguments about which is best.
If you are interested, there is an excellent comparison of the three at [
msts.steam4me.net] . 3DC has a free beginning level program at [
www.amabilis.com] so that is a good one to experiment with. I prefer 3DC because it has many TrainSim plug-ins that save a lot of work and improve accuracy.
None of the programs has a manual, but they have all levels of tutorials and all kinds of help is available in their forums. Please feel free to contact me (please do before purchasing one of the advanced 3DC versions) if I can be of any assistance.
BTW, here is the bottom part of my K-37. All red items are only for alignment purposes and will be deleted.
Bill