Fisher Knerr reached out to touch the model train track, but his father's gentle words stopped him at the midway point.

"No, don't touch," Chris Knerr, 40, said. "See the sign? It says not to touch."

The 3-year-old Fisher nodded, but never took his eyes off the approaching model train. With a whir and a clatter, it went past him into a tunnel.

The Ballwin father and son were at the Model Trains and Military Toys exhibit Saturday at the Jefferson Barracks Historic Park Visitors Center.

Four layouts with model military, passenger and freight trains ran past a variety of model buildings and scenery. Along the walls, there were toy military figures, like the original G.I. Joe, still in their original boxes. Some of the tables had dioramas, models of World War II military scenes. One showed a German camp with soldiers relaxing at a bivouac behind the lines. Another showed Americans attacking a German position.

However, it was the model trains that fascinated the youngsters. They all just stared in wonder as the trains ran lap after lap.

"Fisher has a Thomas the Train at home," said Knerr, referring to the popular PBS children's television show character. "He plays with that at home, but he doesn't have a model train like this."

Oakville residents Doug Engel, 34, brought his son, Samuel, 3, to the center. Proud grandpa, Bill Engel, 66, came along.

Samuel stood by one layout, looking a little bewildered at the lack of action. Then, his father pointed to a tunnel.

"Here it comes, here it comes," he said.

Samuel looked and smiled.

Bill Engel recounted when he had a model train set when he was a kid. However, it wasn't nearly as detailed with buildings, mountains, tunnels and road.

"We just drove it around the track," he said with a laugh. "Then, we'd crash it into things. We weren't collecting them, that's for sure."

Some of the accessories were incredibly detailed. On one layout, there was a Route 66 motel, complete with cabins, parking lot and a neon sign with flashing colored lights. A airport runway stood in the center with airplanes and a control tower.

The free train exhibit was sponsored by the Friends of Jefferson Barracks, a non-profit organization that helps maintain and pay for park improvements. The trains and toys were on loan from club members and other collectors.

The World War II dioramas were donated by the St. Louis County Parks Department.

"There's some fine work in the dioramas," said Robert Dunsford, a county employee at the visitors center. "Some of the (action figures) are pretty old. It's interesting to see."

I commented that little kids especially like the trains.

Dunsford nodded.

"We also get a lot of grandparents bringing their grandchildren to see them," he said. "They all seem to get a kick out of it."

Some more people walked into the visitors center. One little boy in a stroller looked intently, seemingly bewildered and enchanted by the trains running on the tracks.