If you are interested in American Outline Railroading then I recommend My Large Scale and Team Large Scale. 

The former is a long established site catering for all large scale enthusiasts (it is a broad church) whilst the latter is a fairly new presence created by the merger of Large Scale Online and St.Aubin (who claim to be the #1 Large Scale Garden Trains Dealer in the world!).

To access either of these websites just click the hyperlinks above or on the images below.