I'd also be interested in the AC regulator information if Mike or anybody else knows it. Aside from that, and I hope that this does not confuse matters, this 6 Ohm unit may be one of Lionel's champion smokers - if not the champion.
I think that this is the unit that is in the original Legacy FEF-3 issued in about 2009/10 (SKU 6-11116) and the GS-4 of about the same time. If I am right, in the former it certainly produces copious plumes of smoke. The unit is no longer available from Lionel but this is the original part illustration:
The two empty screw holes shown in your photo and the above are for the dual smoke funnel assembly in the FEF-3.
If I am right, the AC regulator Lionel lists as the replacement part is 691ACRG103. In my engines this part has proven prone to failure (Mike himself guided me through the replacement process). I admit that I do not know how it works. I originally thought that there was some element of variable voltage to the heater but as I have just had my FEF-3 on the rails it looks like constant output - and a lot of it.
Downside is that I can't see how this unit could be installed in a different engine from the Legacy ones it was designed for but I stand to be corrected.
