The only difference between men and boys, the saying goes, is the size of their toys. The Greater Baton Rouge Model Railroaders beg to differ.

For the roughly three dozen club members, their toys are the same size as when they were kids. In some cases, even smaller. But their passion for model railroading — which encompasses much more than the trains and tracks themselves — remains as large as ever. If you don’t believe it, a trip to Jackson on Saturday should dispel all doubts.

The club’s annual Trainfest is a real nostalgia-fest for those who long ago packed up their model trains.

For those who have never been introduced to the hobby, it’s a stunning introduction to just how involved it can be.

There are model rail setups in sizes that range from tiny Z scale (which is 1/220th the size of the trains represented) all the way to G, or garden scale, which is 1:22.5. In between are N (1:160), HO (1:78), S (1:64) and O (1:48), and the club also has an outdoor track devoted exclusively to steam-powered trains.

The layouts, which constantly grow and evolve, are in two buildings as well as outdoors.

“We encompass virtually all the scales,” said Bob Coon, the only remaining original member of the club that started in 1986 as the Baton Rouge N-Scale Club. “We’re one of the few train clubs in the country that does.”

The club’s unspoken philosophy seems to be: Go big or go home.

Inside the buildings are an enormous N-scale layout the club has been accumulating for years; a 12-foot-by-14-foot HO layout; an identically sized Lionel (O scale) setup under construction, with its distinctive three-rail tracks; and a slightly smaller, two-rail, O-scale spread. These and the others are working tracks with multiple trains.

What surrounds the tracks is as detailed and intricate as the trains themselves. No detail is spared. Trees, buildings, vehicles, roads with traffic signals, people — whatever the members can imagine and design gets included.

That’s a big part of model railroading’s appeal, said Clay Fourrier, the club’s president.

“I think it’s an all-around hobby,” Fourrier said. “Some people are going to be interested in it because of the way trains run, the way real railroads run. They want to replicate that in miniature. Some people like to build things. Maybe they were model-builders when they were kids or something like that, so they like to build the buildings or the dioramas that comprise the layouts that we have.

“Some people like to be outside, so they build these layouts that have gardens in them and such, and other people really like what the true mechanics were like, the steam engines of the past. Those are the guys in the club that run live steam engines. I’m there because I’m recreating a train layout I might have had a vision of when I was a kid, but never could build.”

This hobby retains its hold on devotees despite the rarity of railroad passenger service outside the Northeast and other large cities with mass transit.

“Everybody probably above the age of 40 grew up with model trains,” Coon said. “As a kid, they had them around the Christmas tree or their dad had them or something like that. I go to garage sales a lot, and I always ask if they have trains. I’ve almost never been to a garage sale where somebody doesn’t say, ‘Oh, I’ve got one in the attic. It was my dad’s or my granddad’s.’ I think every attic in America has a train set in it.

“I’ve been involved with model trains probably since I was 5 years old. I just find it real relaxing,” Coon said. I think one of the neat things about the hobby is it has so many different dimensions. If you like electronics, there’s an area of the hobby that has that. If you like building scenery and dioramas, there’s an area of the hobby that has that. If you like to run model trains like people run real trains, there are a lot of people in the hobby that do that. It’s a very broad kind of hobby. It involves a lot of different facets. It’s just fun.”