I have had for a number of years a postwar Lionel 151 signal which is controlled by a MTH IR controller. There has been at least three occasions in the past where this signals solenoid has overheated due to either using it for a long train running session or by forgetting that a parked train was by the trigger controller. I recently came upon an Ebay seller in China that offers thermal shutoff switches of various types at very low cost. I decided to give this item a try and had the idea of protecting my 151 signal using this thermal shutoff switch. I chose the normally closed version with a shutoff temperature of 50 degrees centigrade. Let me say that after installation of this switch everything is working as I desired and I feel pretty confident that this signal is now better protected against overheating. The key is to mount the metal cased thermal switch up against the part of the signal that you believe will give off a lot of heat. I mounted the thermal switch to the bottom of the solenoid with a strong glue and the side of the thermal switch touching the brass base of the solenoid which I find to get the hottest to the touch when it is overheated. The following photos show the 151 signal and the bottom base of the signal with the thermal protection switch installed. Please note that I did not add glue to the side of the switch that comes in contact with the brass solenoid base, so that maximum heat transfer would take place. I also connected the thermal shutoff switch so that the solenoid and signal light would both turn off together, so that it would be more noticiable that a problem of overheating occurred.
FOR GOD SO LOVED THE WORLD THAT HE GAVE HIS ONE AND ONLY SON, THAT WHOEVER BELIEVES IN HIM SHALL NOT PERISH, BUT HAVE ETERNAL LIFE.
JOHN 3:16
