As a DCC layout, blocking is totally unneccessarry unless the layout is large enough to take up both spots of a double garage, or you can run more than 8 trains at the same time on it. (good luck with that...) Check that the fishplates are attached properly. The tops of the rails should align. If they don't, the fishplate is likely to not be attached properly. Plastic fishplates more than metal can easily only half go on, and that will make the joint uneven. I am assuming new track. On my layout, I used reclaimed track from a previous line, and that made problems with uneven rail wear. The best solution for that was a file, or i bent the fishplates to suit, (The equivilent of lift plates on a real line). XYZ