No sophistication here John. The interface is just a 5v regulator and a double pole reed relay. The switch sends 5v to the relay. One set of contacts goes to the chuff input of the R2LC and the other feeds 5v to the fan motor. If the cam stops on the micro switch the relay is closed and the fan is on.
On this engine there is no wire from the power triac to the smoke unit in the tether. The only control is a switch under the cab. The resistor is a 24 ohm, 5 watt piece connected to the track. Even at 16v its puts out a ton of smoke. This was a quick afternoon project and I didn't really want to get into installing a new tether.
Most of the time smoke will be off. Probably just get turned on for demonstrations. Even at shows I have discovered most people find the excessive smoke objectionble.
I am sorry I didn't order more of these smoke units though as I see it and all of its substitutes are NLA at Lionel. This narrow rectangular unit is the only one I had that would fit is this narrow opening. I will have to check out the MTH units at York.
Pete
