I would search the forums. This has been discussed before.
A dial caliper would be a great help for checking dimensions.
Since the smoke units draw I think about 125 ma, below is a link on how to do this with DCC. Generaly decoders have a 100ma limit I think.
http://www.soundtraxx.com/manuals/Tech_note%2014.pdf
I doubt Radio Shack still sells the relay though.
A Google search for the seuthe smoke units shows a variety of smoke units available. The units also produce heat. It might be an issue in a plastic shell so location might be important.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
What seuthe smoke unit do I use for a Rivarossi 4-6-4 Blue Goose? I have a decoder/sound unit in mind but would like to know what is recomended.