I have a 6-11229 S-3 lionel legacy milwaukee road steam engine and the smoke unit gasket broke in two sooooooo.
I thought is it possible to use a automotive gasket maker in place of the original gasket?
the answer is yes and it works very well in sealing both the smoke stack and steam cylinder smoke chambers.
yes you do have to be mindful of not getting the gasket material on the smoke fan blades.
what I used is permatex red rtv high temp gasket maker rated at -65 to 650 degrees and flash point is from memory above 200 degrees.
I have run this engine twice now both times in excess of an hour smoke at highest setting and nary a hiccup.
I just thought I would pass this on to all here if you ever needed to use/try this option