I don't know if these means that N Scale is growing in popularity, or that the smaller size and convenience of the various N Scale module systems just makes it naturally a lot easier for layouts to be created and set up for events like these, but there must have been around 6 or 7 good size N scale layouts, to perhaps 2 or 3 each in HO and O.
I'll attempt to show a few pictures of the layouts that I came across in more or less the order in which I saw them. Unfortunately, I didn't think to take notes so I can't credit the various clubs or individuals that were behind such great works.
To start, love the beautiful track work on this layout. Truly humbling!
Another shot of the same area from a different angle:
Of course, in addition to the N Scale Layouts, there was lots of other stuff.
This layout / diorama has been present each year. I don't know quite what to make of it, but it seems to be an O Scale diorama of an abandoned mining line with lots and lots of rusting material strewn all over. Its a fascinating diorama that always invites my attention!
* Not really in Seattle, about 30 miles North and East in a town called Monroe.