Working on the HO scale modulars for the Christmas Forest, I found I had to replace a section of track with an 18" radius "S" curve. Attempt fit, file, fit again, etc. Get all done and put it in for permanent - SNAP! I lost two ties on the one end. First ties I've lost working with flex track in decades. Sigh. I think I was trying to use too large a gauge of wire on the feeder on the bottom of the rail joiner (another configuration I don't normally use).