I, of course, live in an area - like most, really - where train shows are not "common"
at any time of the year. In fact, they are as likely in the summer as the winter, here.
There was one in Tallahassee FL in July. 2 in the Mobile area - March and Sept. Swap meets here and there. But, pretty thin compared to the RR belt and its outposts (central and south Florida, for example).
But, there often seems to be a feeling - I even hear it here - that train shows are strictly "buying" events. I don't look at them that way; I go mainly because I'm a RR hobbyist and so is everyone else in that building for 1 or 2 days. Things in common. Model RR atmosphere. Birds of a feather flock together.
I/we drove to the Tallahasse FL show - a pretty good drive from Mobile - and I spent $20 at the show. Mostly books. That's it. Enjoyed the day; had some laughs. Now, the vendors may not like that - and I am one at local area shows, usually - but sometimes I go because I can't see why you wouldn't go, just to hang a bit with your peeps.
Next show I may find that 4-10-10-6 that I've been "needing" for years, at a "good price". Probably it's cost me more than $20. Or I may just buy another book; either way, it's usually fun.