ALL THIS technical wizardry and obsessive detailing doesn’t come cheap; big boys and their big toys equal big money. According to the most recent research by Kalmbach Publishing, the industry is worth about $1.2 billion annually. That’s a lot of trains.

And the billion-dollar business sells much more than that. Allen Keller, the instructional-videos maker, also runs the Model Railroad Skills Institute, an annual three-day seminar for first-timers. The cost? $1500. To feed their insatiable hunger for railroad history, miniature-train buffs pay researcher Jennifer Eble up to $30 an hour to dig through the collections of Kalmbach Memorial Library, the research arm of the National Model Railroad Association in Chattanooga, Tennessee. Prototypic modelers " will go as far as wanting track maps of a particular location on a particular year on a particular day, " she says. " We’ve had people ask for photographs for the certain town around the certain station. They will ask for 360-degree views of everything. They just want to get everything exactly. " Eble estimates that the railroad library, which houses 200 magazines, 3500 books, and 50,000 images, typically fields up to 200 requests a month.

" I’m a member of the National Railroad Historical Society, I’m a member of the Railroad Enthusiast, I’m a member of Erie-Lackawanna, a railroad that used to run through Pennsylvania, " ticks off Roslindale’s Bob McLaughlin. His friend Jack Harris, who has a garden layout in his back yard, subscribes to six monthly model-railroad magazines and regularly adds to a growing collection of books.

Lynn Johnston, creator of the nationally syndicated cartoon For Better or For Worse, says her husband Rod, whose railroading obsession she chronicles in the cartoon, has been known to overspend on his garden layout in the back of the house. " I enjoy it and I always know where he is, but there are times when he does blow the budget on stuff, " she says via phone from Ontario, Canada. " And then I say, ‘But dear, it’s a toy.’ "

" Do-it-yourselfers are notorious for spending thousands of dollars on something they [won’t get a return on], " says Steven Gelber. Even if modelers work from scratch, as do George Sellios and the Roslindale club’s members, costs can soar. Last term, MIT’s TMRC spent about $3000 on supplies, according to Knight, the club’s treasurer.

The Roslindale club covers its costs with $15 monthly membership dues, but it’s also fortunate in that it owns the building it’s housed in: several commercial tenants bring in rental income. In fact, McLaughlin eagerly points out, they’re only three years away from paying off the mortgage.

But the MIT modelers have taken a more unusual approach to funding their pastime: cashing in on their neighbors’ thirst. Several years ago, the club bought a Coke machine that sits in the building’s entrance. The modelers make a return of about 25 cents a can. " We buy in large quantities from the Star across the street, " explains Knight. " We go when there’s cheap soda. Two dollars for a pack of 12 is really good, but that’s really rare. Usually it’s $2.66. " Suddenly a scrawl on the club’s board makes sense: Barq’s and Minute Maid on Sale — We need more Sprite, but no more at Star across the street (as of July 4).

MIT’s Model-Railroad club was established in the late ’50s — at the zenith of the popular interest in miniature trains that had sprung up throughout Europe and the US in the 1870s. But unlike their contemporaries, according to Steven Levy, Newsweek senior editor and author of Hackers: Heroes of the Computer Revolution (Penguin, 2001), MIT club members distinguished between those who worked " below the table " on electrical components and those who worked above it, lavishing attention on model replicas and trains. Levy credits the early MIT club with coining the term " hacker " for those who pursued below-the-table technical virtuosity for the sheer pleasure of it. It’s no wonder that computer wizards in the next generation appropriated the term. In the world of Big Science, Levy argues, " the computer has replaced the model-train set. "

Now that computer technology has triumphed and rail transportation has declined, it’s the hackers at MIT who appear to have the best chance of ensuring the hobby’s future: their club attracts people of all ages, from undergrads to retired alums. In the face of their technological innovations, the joys of tiny trains and trees seem old-fashioned indeed. Lynn Johnston says of her husband: " Rod thinks he might be the last of the line of train fanatics. "

But he’s not alone yet: as Sellios and the Roslindale model engineers make clear, the above-the-table approach still inspires passion. These hobbyists are driven by an impulse to fill their leisure time with work-like activities, says hobby expert Gelber. " What I think is going on there — if we avoid passing judgment on these people’s anal-compulsive behavior — is the concept of expertise. " And sure enough, at the Roslindale club, everyone has his specialty. Ian Kempf is an old-car and truck guy; Jack Harris is into buildings; Bob McLaughlin is a scenery buff. The work is play.

Like middle-aged women who construct and furnish dollhouses, model railroaders are mostly adults reviving a childhood hobby. They may be constructing different things, but all the elements of control, consumerism, and craft are the same. For both, modeling and tinkering is not only intensive and expensive, it’s exceptionally satisfying. So too is mastery over a miniature world entirely of one’s own making — just at the point when control over one’s own work life is slipping away. " There are many parallels between the two, " notes Candace St. Jacques, the editor of Dollhouse Miniatures magazine.

Many kids play with model trains until puberty, and if adults are going to return to it, it’s most common to do so in the late 50s or in retirement, says Gelber. Lynn Johnston says her husband’s garden layout is modeled after a train that he rode as a kid. McLaughlin and Harris lovingly recall their own first train sets. " [It’s] childhood re-enacted, " explains Gelber. " The meaning shifts somewhat. There’s a lot of feeling that for children, it’s part of a developmental pattern. Whether adults are rediscovering their childhood, well, I’m not really sure. "

At Wednesday’s meeting at the Roslindale club, the phone rings in the corner of the room. " Does anyone want to answer that? " calls out Jack Harris. He surveys the room of men consumed with fiddling, painting, and tinkering.

The boys keep playing.

Nina Willdorf can be reached at nwilldorf[a]phx.com

Additional reporting by Julia Cohen.