Not really too worried...So far the stuff I've built is pretty reliable. (...pats self on back...) There now I've gone and put a hex on the whole damn deal. Actually, I was thinking about leaving a 1/4 relief in some areas when I install my masonite facia. That and install items like power/telephone/light poles in areas where things get a little close to the edge. That is still no guarantee, as I had a caboose roll off the table as a result of a rather violent "bump" several weeks ago and it was two inches from the edge. Luckily, the caboose was not severely damaged and didn't break. That was from a 5 foot drop onto a concrete floor too! Eeeek! Also still, its not like I'll have stuff rolling through there at Main Line speeds. Most traffic in the yeard is only moving at a crawl.