Answer: When it's K-line Supersnap track.
I saw some K-Line SuperSnap curves on 'de Bay. O42 - 12 make a complete circle. Seller only had 10.
Same seller had 1/2 O42 curves also, so I bought 4 of them to make up the two missing full curves. Makes sense right?
Except, a Half Curve O42 SuperSnap plus a Half Curve O42 SuperSnap is NOT EQUAL TO a Full Curve. It's longer!
Am I missing something?
Ed
ps. Walter... we need some new RMT Supersnap, please