If you live in a northern clime, chances are you've taken a look at my posts concerning roadbed construction and thought, "Wow, this dufus is gonna be real surprised come the Spring thaw!" Well you might be right. I have built a house, barn, and sheds by hand so I'm not a complete n00b in construction methods.
Truth be told I am a little worried at what I'm gonna find when the snow melts next year but the method is not without precedent. The folks at the Ottawa Valley Garden Railway Society are using a similar method though they are using the DekBlocks system which is a bit more expensive.
While I'm at it, let me recommend the huge bulk of garden railway information to be found at Family Garden Trains. Anything you'd like to know about outdoor trains can be found here.
**ADDED NOTE** I have had several people insist that Lego bricks will not last outdoors. Miniland would seem to debunk this notion as would the test sections of RC/PF track I have kept outside for the past year. Time will tell