O-31 switch won't toggle

I would bet that the problem is that one or both of the he control rails are making contact with their adjacent outside rails. That would account for the switch working properly when off the layout yet failing to throw when installed on the layout.

Examine the switch to ensure that the ends of the control rails are not touching their adjacent rails and that there isn't any connection of the control rails to their adjacent rails under the switch, either,

Barry,

Thanks for your post. I've checked at the switches for shorts and there are no issues I've detected. All tghree receive power and the lamps illuminate on the switch and controller.  I tried disconnecting the external power and jumpering to track power for the two malfunctioning switches, but the symptoms remain the same for both, they will not toggle. Since I have two of the three switches remoted through two sets of screw terminals (one working, one not), I will start at the switch controller and trace each wire for both the operating and non-operating switch looking for a wiring error or short. Since one remoted switch works and one malfunctions, and a third switch directly connected to its controller also malfunctions, retracing wiring seems the best next step in search of the problem.  Somehow, signal or operating power is keeping the two switches from toggling.

Again, I really appreciate your taking time to answer!

ChasP

The problem is not a "short circuit", per se.

Rather, it's an unintended connection between the switch's control rails for automatic non-derailing operation, and the outside rails of the tracks that are adjacent to them.

Thanks Barry.  That helps me understand the symptoms and the switch behavior and I should have recognized the non-derailing feature as the problem cause.  But while I understand Lionel switches and their use of insulator pins on the interior common rails to provide the break in contact, I hadn't noticed that the MTH interior switch common frog is designed with no contacts.  In-attention to detail I guess!

I insulated the frog rails on each switch with a small tab of electric tape and that resolved one switch.  The other now operates correctly when the terminals are shorted at the switch, but not from the remote controller.  So, I guess I will be tracing thet wiring on that switch to finally resolve the problem, but thanks to you I am on the road to total problem resolution!  

ChasP

Barry,

Problem finally solved.  One switch continued to not respond and I finally reran the wiring using sprinkler 8 strand coax for the final 4 feet, replacing finer wire with more robust #14 wire. It resolved the issue and permitted ganging of two switches on one controller, one of the outcomes I was unable to get working earlier.  It was a mistake on my part in wire choice at the outset!  LESSON LEARNED: choose wire more carefully and, when in doubt, test run lengths before installing!

Thanks for your replies through this post strand.  Your encouragement was what kept me going and your insights convinced me that when I upgrade to DCS at some point I will buy your book!

Again thanks!

ChasP