Just received my first set and was mildly disappointed. I found it difficult to keep the units together out of the box and tried a dab of super glue. Then I realized the wiring did not make good connection to the tracks. My remedy was to: -take the plastic stop piece off the rails -snip off the end ties from the tracks -with the lights in place and wires pulled tight through the plastic then I soldered the wires to the rails They seem to work fine now but look a little rough. If I was better with the soldering gun it would have snapped back together better but I got the assembly a bit hot so be careful.

Wires to the light don't make a good connection. There is a way to correct this design flaw. Attach the wire to the rail using half of a track joine