I thought I'd finally fixed all the problems with the MTH STD-72 switches on our museum layout, but Murphy's Law came back and bit again. In our yard there is a short section between two switches where I had not bothered to put a power feed, since it could take power from the switch from the main line. The other day I discovered that section (2 or 3 pieces of track) was dead. Checked with a VOM and the connection between the center rail on the straight path and the curved path was open. All three center rails (inbound, outbound straight, and outbound curved) are connected internally by wires, so why was one side dead? I opened it up and the wire going to the diverging path was broken - burned to pieces. It was easy to see why. MTH had chosen 26 gauge wire to transmit track power to the diverging path. The poor thing just blew up from too much current draw. All the other wires in there are 26 gauge too, but that's OK because all they carry is signals for the non-derailing feature. I replaced the offending wires with 18 gauge and I don't expect any more trouble, although I am going to put a power feed on that little section between the two switches just for insurance.
Here's a picture. The blue wires connect the center rails. The one to the diverging path (center and lower right) is blown to pieces. You can see a stub attached to the track clip on the diverging path. You can't really see it in the picture, but the other one shows some signs of overheating.
