The TCA Eastern Division event is a train MEET, not a train SHOW. There really is a significant difference between the two, even though I've found over the years that many people have a hard time understanding the distinction.
Basically, though, a train SHOW is where folks go to see what this hobby is all about. Usually has a number of operating layouts in various scales so people can view not only individual products (which are also there), but can see how these products are used and can be used.
A train MEET is where folks go to buy/sell/trade stuff and, if the meet is large enough, to meet up with manufacturer representatives and other industry movers and shakers.
The TCA Eastern Division puts on their event for their members. They generously open it to anyone else in the TCA who may care to attend, and, more recently, to anyone--including the guy walking in off the street--who has the $ to join the TCA (on site) and pay the admission fee. ANYBODY who cares to can attend the York Meet these days.
The York MEET is the largest event of its type on the planet.