Play Yet Another Tune for America's Love of Diners

THE Pig 'N Whistle diner in Brighton, Mass., is a quintessential 1950s diner: a freestanding rectangle of stainless steel, chrome, Formica, and Naugahyde.

Inside, the grill sweats mouthwatering aromas into the air. A short-order cook cranks out specials while one waitress tends the counter and another the booths. Each table has a mini jukebox, of course.

The name Pig 'N Whistle has something to do with a train and a slaughterhouse that have long disappeared. But no matter. The word is, when you eat here (pig) you leave happy (whistle).

On a Saturday, the place pulses. As in any diner worth its salt, breakfast is served all day and the waitresses can pour without looking.

Whether you're at the Empire Diner in New York, Mel's in San Francisco, the Silver Diner in Washington, or Charlie's in Boston, diner cuisine is Americana at its hungriest.

Some diners serve good food, others specialize in greasy-spoon fare, but service is never slow and meals are not expensive.

''Good diner cuisine is what you would expect if you went to Grandma's house,'' says Myles Henry, co-owner of the Maine Diner in Wells, Maine, where meatloaf, pot roast, and turkey are big sellers.

While more Americans may be rediscovering diners, the roadside eateries have never really gone out of style. Artist John Baeder has made painting diners in the Photo-Realist style his passion for two decades. Movies, television, and books glorify them. Political candidates and reporters go to diners to talk to ''real'' people.

''Americans have had a love affair with diners 'forever,' but only in the past 10 to 20 years have diners captured the fascination of more-enlightened entrepreneurs,'' says Richard Gutman, author of ''American Diner: Then and Now'' (1993, HarperCollins).

Today, older authentic diners clank along like well-tuned antique cars, while newer diners - Mediterranean, Mexican, and Colonial styles - dot the suburbs, their gigantic desserts orbiting behind Plexiglas.

Copycat ''theme'' diners, such as Ed Debevics and Johnny Rockets, flourish, nuzzling up to baby-boomer nostalgia.

Then there are old-style diners that serve upscale food, such as Fog City Diner in San Francisco and the Buckhead Diner in Atlanta. No one foresees local diners replacing meatloaf with mussels fra diavolo, however; or - horrors! - suggesting reservations. But even small-scale diners are evolving. Some offer lighter and vegetarian fare along with regular dishes.

''The wide range of food is what made diners successful fast-food restaurants in the first place,'' Mr. Gutman says. ''The hallmarks are: Give people what they want to eat, and give them a good value.''