It’s no secret that the U.S. railroad system, which a century ago had the largest passenger service in the world, looks very different today.

Though the nation’s freight system is still significant, passenger service has long since been eclipsed by automobile and airline travel, and many railroad companies that once offered service between smaller cities and towns have long since disappeared.

But there’s at least one place where railroads still reign supreme.

Over the last weekend in January, nearly 22,000 people flocked to the Eastern States Exposition grounds in West Springfield, where the Amherst Railway Society held its annual Railroad Hobby Show, bringing together rail enthusiasts from across the country — as well as from Canada, Great Britain, Australia and Denmark.

Nearly 360 vendors, spread out inside four spacious buildings, sold an enormous mix of model railroad supplies: engines and train cars of varying sizes, miniature buildings and natural scenery, tracks and lighting. You could also find photographs and postcards of vintage trains, books on railroad history, and wooden train sets for children.

For Joseph Collins, a longtime model railroader who lives outside Hartford, Connecticut, the Amherst Railway show, which began under more modest circumstances in the late 1960s, has become a can’t-miss event, one he’s been coming to for over 15 years.

“I started in this hobby when I was about 11,” said Collins, who copped to being in his 50s. “This is the best and the biggest (railroad) show I’ve ever been to, with just a ton of stuff. And it’s great to see some familiar faces each year.”

Ralph Ginges, who runs Ralph’s Trains, a model business in Virginia, said he’s been coming to West Springfield for seven years. His business specializes in flatcars that are topped with a range of heavy machinery and equipment, from excavators and tractors to military vehicles such as tanks.

“This is the biggest show that I know of, though I’ve heard there’s a pretty big one in Milwaukee,” he said. “I love coming here … business is always good, and there’s a lot of enthusiasm.”

Then he leaned over the edge of his booth to hand a free booklet on trains to a young girl who was with her father. “You can run a machine just like a guy can,” he said.

Officials with the Amherst Railway Society, which started in the 1950s as an informal group of students and faculty at the University of Massachusetts Amherst, say their annual bash is the largest railroad hobby show in North America. In the program for this year’s show, President John Sacerdote wrote that the event is “now known as the ‘Bucket List Show.’”

Philanthropy is also a part of the event, according to Gregory Maas, the Railway Society’s director of communications and marketing. He says the society, since 1991, has donated over $814,000 from money raised at the hobby show to railroad historical and preservation work across the country.

The huge model train layouts are a major appeal of the event. This year there appeared to be none longer than the one built by the Reading Company Technical & Historical Society, a Pennsylvania group. A sign by the sprawling and intricate rectangle of track and miniature buildings said it was 160 feet long — and that the group’s first display, from 1983, measured just 10 by 12 feet.

Nearby, the New Hampshire Garden Railway Society also had an impressive setup, a looping arrangement of track on which chunky steam locomotives pulled vintage railway carriages and old-fashioned boxcars.

Joe Lupinksi said he and other club members come from all over New Hampshire and enjoy the Amherst Railway Show for the space it provides for these large displays: “It’s something we really look forward to.”

Closer to home, the Dry Hill Model Railroad Club, from Montague, had put together a detailed layout focused on modern urban landscapes; the model trains ran past busy roads filled with small cars and trucks and a large sign displaying the logo of the Philadelphia Eagles.

But for sheer intricacy, perhaps nothing topped the work of the Central New York Modelers, a group based in Syracuse, New York, whose members had built a wide variety of backdrops for their trains. Those included wooded sections inspired by the Adirondack Mountains and detailed Northeast urban settings, circa 1940s to 1950s; one set featured figures playing basketball in an alleyway.

The group’s work previously won a “Best of Show” award at the Amherst Railway show.

“We’ve been coming here for over 20 years,” said member Bill Brown. “It’s always a good experience.”

He also said the model train hobby in general is a great way for rail enthusiasts to get together to share their love of railroad history and building detailed layouts for the trains. “A lot of thought and energy goes into this, and a lot of good friendships are built from it,” he said.

Steve Pfarrer can be reached at spfarrer@gazettenet.com.