When you lay model flex track, does the sliding rail go to the inside or the outside of the curve? This thread, by a majority, puts the sliding rail on the inside of the curve. Others disagree; others say it doesn't matter, especially when creating large radius curves. In any case, this is a good discussion of the issue by several members. I will add that, indirectly, this also involves whether the gapped ties on flex track go to the inside or the outside of the curve. For some of the newer flex track types, neither rail slides, but there is still a gapped and an un-gapped side to the ties. I can only think that this thread will have more and more posts. Additional search terms: cork roadbed ballast spiral easement radii Peco Atlas Kato