NEW YORK -- Why, people have been wondering sadly for decades, why is there no truly first-class delicatessen in greater Washington? No perfect pastrami on the Potomac? No kishka in the Capital?

Leo Steiner, who runs the Carnegie Deli, doesn't wonder.

"If you wanted to run a deli, would you go to Washington?" Leo demands. "Nobody wants to go to Washington to make corned beef. If you want to make policy, maybe.

"But you have to be far more qualified to make corned beef than to make laws. Whaddya have to be to make laws? An actor, maybe." Whereas to make corned beef, he doesn't need to point out, you have to be a vociferous New Yorker who learned the secrets of pickling spices at your Hungarian grandmother's knee. You need honed taste buds and strong arches. It may be genetic.

"You gotta remember, what's the wonderful thing about a deli?" Leo is proclaiming. Leo never sounds irresolute about anything, least of all about eating and eateries. "The wonderful thing is, 90 percent of the people in this country can go into a deli and know what they're eating! A lotta places -- you walk into a fancy Italian or fancy French restaurant, all these fancy names -- you don't know what you're getting. And after you're outta there, you're still hungry!"

A painful thought. Waiters within earshot at the Carnegie, where Leo is holding forth this morning, pale at the prospect.

"Now, you're a lady," Leo goes on, reasonably. "You'd probably want a nice nova and cream cheese on a toasted bagel. The fella with you, he'd probably want a good corned beef or pastrami or a combination. Cake for dessert, you're getting a nice piecea cake.

"You know you can eat and enjoy!" he concludes, triumphantly. "People feel SECURE!"

The preceding rhapsody has been occasioned by what promises to be a significant sociocultural event: the Carnegie Deli, since 1935 a fixture of Seventh Avenue and widely argued to be New York's best, will officially open a Beltway branch tonight, with Leo himself in attendance. Also Henny Youngman.

Local deli mavens, a sorrowing lot frequently reduced to toting aromatic bundles south on the Metroliner, are experiencing twinges of skepticism. For one thing, this branch of the Carnegie will be housed in the Embassy Suites hotel in Tysons Corner, where things are a bit on the new and glassy side. Thirty deli people -- waiters, counterpeople, the chef and the hostess -- have been imported from New York and from Jersey to run the place, but how long will they be willing to live and work in exile? And can even Leo Steiner, 47, featured in Woody Allen's "Broadway Danny Rose" and in Arnold's rye bread commercials as the quintessential deli man, find top-seeded rye down there in mega-mall country?

But these are doubts that can be, um, swallowed for now. Up to 800 people are expected at Tysons Corner tonight to help Leo and developer Bruce Goldstein cut the ribbon (with a meat cleaver) and the cheesecake. Mavens, despite misgivings, try not to drool. Nonmavens, here is what to expect.

First, about the food. The food is the thing here. It's why everything is served on plain white china, the better to set off the blush of the smoked salmon, the golden sheen of the chicken broth. It's why no one can remember the last time the New York Carnegie was remodeled. To have the grungy ceiling tiles or bashed-up light fixtures replaced, Leo would have to shut down operations for a few days, which is unthinkable. "If I redecorate," he says, "I have to let people starve."

Instead, let them eat nova (as in Scotia, as in salmon), which he's arranged to have trucked to Tysons Corner by his regular supplier in the Bronx. "You look for a light color," he advises, peeling a silky slice of nova from a tray behind the counter. He's off on a gustatory lecture tour. "Taste this. You get the flavor of the salmon, you don't get the salty flavor, you don't get a fishy odor." Noted.

"Salami," Leo announces. Several dozen dangle overhead. "Salami must be kosher salami; otherwise, forget it." Right.

It's hard to turn around in this narrow alley of sliced meats and pickle barrels, though easier for Leo since he lost 70 pounds. (How? "I starved.") Still, he needs to taste, doesn't he? With a plastic fork, he spears a crumb of rugelach cheesecake, dessert specialty of the house. It consists of those buttery-and-cinnamony pastries called rugelach chopped into crumbs, stirred into a cheesecake the diameter of a beach ball, the concoction then glazed with chocolate. How many calories are there in a slice? "Don't ask," says Leo, bouncing in his molded orthopedic shoes toward the kitchen.

It is a steamy Hades, clouds billowing from the 55-gallon pots of chicken soup, flames flaring beneath frying pans of sturgeon-and-onion omelets. If things get too slippery underfoot, someone strews the floor with kosher salt.

The chef is attending to the cottage cheese filling for blintzes. His name is John Kuo, an e'migre' from China who has become, according to Leo, "the best Jewish cook you'd ever want to find." Among Chef Kuo's top assistants are Miguel Aylan and Julio Cardinales, further demonstration that ethnic food is not always what one expects.

"Come, come," Leo says, heading down to the basement. He tends to say things in pairs, like "sit, sit" and, especially, "eat, eat." Downstairs, he pats the pastramis, encrusted in spices and ready for their 12 hours in the smoke oven. (Which spices? "We're not going to tell you.") In the walk-in refrigerator, stainless steel vats hold the corned beef, already pickled for nearly two weeks, then cooked. (For how long? "Till they're ready.") A vast bowl of chopped liver awaits seasoning. It should be, Leo says, taking a pinch, "a little on the coarse side." It should also be made with chicken fat, of course.

All these items are served in quantities that defeat the average appetite. The cakes come in slabs; the sandwiches contain a good three-quarters of a pound of meat, unless they're combos, in which case they contain considerably more. ("A sandwich," Leo insists, "should be a sandwich.") Sergeant Slaughter, one of the pro wrestlers who comes in regularly, can eat two doubles (corned beef plus pastrami, maybe 2 1/2 pounds of meat, total) at a sitting. But then, he weighs 300 pounds.

Certain popular foods, notice, are among the missing. "We have no croissants here!" Leo declares. "You can't get an expresso here! We're not pushing foreign food. This is American!"

Now, about the atmosphere. (You don't talk about ambiance in a deli.) Perhaps the best way to describe it is haimish (homey, unpretentious), because people here are as loudly opinionated as they would be in their own kitchens. Lunch hour at the Carnegie involves a lot of shouting.

Say you come by about 12:30, when customers are lining up outside on Seventh Avenue. You finally work your way to the front of the line where hostess Lena Wachunis schmoozes briefly ("You keep your mother waiting?" she chides one late-arriving son) until Herbie -- that's Herb Schlein, Host to the Stars -- spots an emptying table.

"Lena, two!" he yells.

"Two!" sings Lena, going down the line to find a party. She gives you menus and says, "Enjoy." You navigate the narrow aisle between the long communal tables, trying to avoid stuffed exiting diners, kitchen help lugging food, waiters and waitresses, and Herbie.

You place your order -- if the waiter approves. "It's bad when someone comes in for a hamburger or a tuna salad," clucks waitress Flora Rivera. "You act very shocked. 'You come into a deli for that? You can get a tuna sandwich anywhere; pastrami, you can't.' "

"I tell them, 'corned beef, pastrami, brisket, tongue,' " chants waiter Richard Senior. Customers capitulate "nine out of 10 times. I'm very persistent; I tell them we're out of ham-and-cheese."

The waiters go to the counter and yell their orders. Then they yell their drink orders. A few minutes later the "expediter" (today it's Manager Steve Denowitz) yells everything again. When the order's ready the countermen, skilled pros who can tell how much meat to pile onto a sandwich by heft alone, yell some more.

"Three briskets!"

"Ordering two CBs." (A CB is a corned beef sandwich, of course.)

"A Reuben!"

"Pistols, a pair!" (Denowitz explains, between bellows, that a pastrami sandwich is called a pistol so no one confuses it with a salami sandwich.)

"Ordering a pistol on pump." (Sandwiches are presumed to come on rye, unless pumpernickel or a roll is specified. White bread and whole grains you don't discuss here.)

"Whiskey down!" (Translation: rye toast.)

By the height of the lunch-hour rush, the pace picks up like a record played too fast. "You waiting for something?" Murray the counterman demands of someone who fails to place a takeout order with sufficient alacrity. Herbie and Lena are shuttling people in, double time: "Two! Let's GO!" The waiters start removing your plates if you linger past half an hour. A squabble breaks out behind the counter as to whether a takeout order was half a roast chicken or a whole roast chicken cut in half. A squadron of nine deliverymen dashes through midtown bearing pistols and CBs.

"You call my borsch?" Flora Rivera asks the expediter.

"I got a borsch!" Denowitz obliges. "I got two hands," yells the counterman.

"He's got two hands and a big mouth," Rivera blasts back.

Writer Noel Behn, a regular whose deli dining partners used to include the late Bob Fosse and Paddy Chayefsky, wades in to cash a check at the register. He looks fondly over the mayhem. "This is the most New York thing we could send you," he says, "after Ed Koch."

Which raises the uncomfortable question: Can something this New York really be transplanted to Tysons Corner? "Never!" protests one regular customer. (You can tell because Herbie's awarded him the Carnegie's own status symbol, a linen -- not paper -- napkin.) "How can you duplicate this? The dirty ceiling, the flies on the wall, Leo waltzing around. They'll be too polite in Tysons Corner."

Indeed, certain concessions have been made. The Embassy Suites people have requested fancier china and what developer Goldstein calls "slightly more upscale de'cor," which Leo frets may "ruin our image.

"But I guarantee after three months, all our waiters will look like that" -- he's gesturing towards the distinguished Jack Sirota of Brooklyn, who looks like he knows a thing or three about enormous sandwiches. "You walk into a deli, the waiters are skinny, you know the food's no good."

Well, but. The New York Carnegie opens each morning at 6:30 and stays open till 4 a.m., so that show people can unwind over potato latkes and whitefish. Those gabby, nostalgic comics who hung out at the Carnegie in "Broadway Danny Rose" were not much of an exaggeration. Jackie Mason comes in all the time; so do Jerry Stiller, Anne Meara and Woody Allen himself, and Leo's good pal Mr. T. Also Henny Youngman. (And Henry and Nancy Kissinger last year, but they're not so funny.)

The Tysons Carnegie is not going to get a crowd like that, even if it is surrounded by 13 million square feet of occupied office space, and it's not going to stay open past midnight. "Senators gotta do something at night, but it's not eat," Leo figures.

And what will Washingtonians think of the decibel level? Or of paying close to 10 bucks for a sandwich, even a towering one called "Tongue's for the Memory" or "Beef Encounter"? Several decent area delis have gone under, like Zeltner's in Chevy Chase and Mandel's in Bethesda. For that matter, the Carnegie's only previous excursion past New York and Jersey (there are branches in Secaucus and Atlantic City), a shopping mall deli in Fort Lauderdale, was a marginal operation that Leo and his two longtime partners decided to close after a year and a half.

But why rain on Bruce Goldstein's parade? The guy's a real estate wheel from Minneapolis, for heaven's sake, a place where you absolutely cannot find world-class pastrami. For 20 years, he visited the New York Carnegie on every business trip, even if he were in town for only half a day. In two decades, Herbie never gave him a linen napkin, but he loved the place anyway.

Now, after 15 months' arduous negotiation (Leo told him the agreement was "too thick" to deal with) and a mere half-million of his own dollars, Goldstein has brought the Carnegie to Washington, sort of. And he's getting his own Goldstein's Sampler (matzoh ball soup, half a pastrami sandwich, a potato latke with sour cream, a scoop of chopped liver) on the menu. And tomorrow night, he's going to celebrate that achievement and his 40th birthday there, with his wife and lots of friends and Leo. Also Henny Youngman.