The meet I went to in Oct was 'just right', good number of tables, spread way apart, huge center aisle, maybe 40 feet across, easy to stay 6 or more feet away from others, open on all sides. Crowd was not huge, so never felt close to others. The stuff doesn't live well on hard surfaces, so I do not believe the risk is high from picking it up from trains. I wasn't touching anything at any rate, unless I was serious about it. Can always run and wash your hands. Depends on how much you like train meets, I miss them greatly, and this was a nice event given that two Yorks were already cancelled, the height of my train year.
Jim