It's a slow rainy afternoon here in Mill Valley, so let me try respond to some of Gothguy's questions/issues. Don owns this place and he has the final word, but I was one of the original moderators.
This place started out as being pretty C&TS oriented, and expanded (a little) from there. So I would say that steam powered AND narrow gauge AND North American are the primary focus. Beyond that it gets a little touchy feely. Anything narrow gauge (non-steam or foreign) is probably just fine so long as it does not dominate the discussion. Anything standard gauge and steam is okay in small doses. Standard gauge diesel is a bit out in left field, although some some lines like the SLURG seem to have become honorary ng. because of their proximity to the C&TS and interesting activities.
I suppose one fairly clear no no is posts trying to sell stuff commercially or for personal gain.
This is a discussion group and not closely moderated, so to some extent the content will wander wherever the posters want it to. I would say the key question to ask yourself before posting something is simply will it be interesting to the folks who read this place. Of course there is not always a clear answer, but if in doubt hit the delete key.
Now if he is so inclined Don can tell you what the real rules are.
JBWX