Lynn,
If you go to this page and download the scale & gauge PDF you should have all the information you need. It's under "download booklet sections."
http://www.greatesthobby.com/wgh/default.aspx?c=a&id=84
Rene
Rene Schweitzer
Classic Toy Trains/Garden Railways/Model Railroader
Paul Race wrote a good article about "scale" as related to garden railroading that you can access at the following URL: http://www.btcomm.com/trains/primer/whyscale/whyscal.htm .
Otherwise, you might have to be more specific if you are looking for information not contained in that article.
Enjoy!
-GB
Get the Garden Railways newsletter delivered to your inbox twice a month