NEW YORK -- It's not your ordinary Madison Avenue approach. In these television commercials, sort-of-satisfied customers offer testimonials like, "Granted, it could be cleaner," and, "When somebody's putting their elbow in your ear, you have a sense of humor about it."

But then it's not your ordinary product that's being shilled in these 30-second spots. It's the New! Improved! but still very far from perfect New York City subway system, and the challenge to the small ad agency that crafted the campaign makes post-tampering Tylenol and de-benzened Perrier look like easy sells.

"If the campaign had smiley, happy people saying, 'I ride the subway and I love it,' people would wonder what planet you were from," says Joe Cianciotti, who for most of the campaign served as copy supervisor at Bergelt Litchfield Raboy & Tsao, the Metropolitan Transportation Authority's ad agency. John Lender, the MTA's own marketing director and a man of unusual candor, acknowledges that the subway has served as "an international symbol of urban decay."

So Bergelt Litchfield avoided bouncy jingles, euphoric models, warmed-over Motown and other Adland staples in the campaign that's all over New York's airwaves. Instead, you get real riders with outer-borough accents, like two yentas from Queens named Clara and Phyllis intoning, "You have to be patient ... these things take time." And real maintenance workers like Rocky (honest), who's fixing the tracks on the Manhattan Bridge while commenting, "We bust our butt every day." You get quick, kinetic editing of transit images, a soundtrack of milling crowds and clacking rails, and finally a superimposed slogan: "The Subway/ We're Coming Back/ So You Come Back."

It's too soon to know whether even a stylishly executed ad campaign can lure recalcitrant New Yorkers back onto the subways, whose ridership grew through the '80s boom but has been declining since late last year. Some transit critics argue that it's wrongheaded even to try. This phase of the ad campaign costs about $2.1 million in production and media time; meanwhile, the Transit Authority has cut $80 million from this year's budget because of lower revenues and reduced government subsidies.

"If I had 2 million to spend on the subways, I'd hire some more token clerks so I wouldn't have to wait on line with 60 crazed New Yorkers," says Gene Russianoff of the Straphangers' Campaign, a riders advocacy group. (The Jan. 1 fare increase from $1 to $1.15 lengthened lines at token booths.) Russianoff likes the new ads but thinks they're a waste of money. "You can't market sour milk," he says. "For hundreds of thousands of riders, their {subway lines} are still not decent... . It's premature to crow and expect people to believe it."

The Transit Authority has a citizens advisory committee whose director, Beverly Dolinksy, agrees that "to spend money on advertising when you're cutting back in service is not good for your customers."

But Lender, chief flack for the MTA (of which the Transit Authority is a member agency), points out that the TA is spending only two-tenths of 1 percent of its operating revenue on advertising, and argues that it's a vital investment: "If you just let ridership go down and you do nothing to get it to increase, you permit a self-reinforcing spiral that runs on forever and results in further cuts and a worsening situation. We simply have to act."

So last year, after Bergelt Litchfield beat out more than 30 agencies, many bigger and better known, to win the subway account, it launched Phase 1 of this uphill fight, with newspaper, radio and transit ads. The objective was to tell New Yorkers, particularly the 35 percent who are infrequent users, that the much-maligned subways were getting better.

In many ways, they were. Since the system's generally acknowledged nadir in the early '80s, before a capital improvement program began pouring $12 billion into subways and buses, the Transit Authority has purchased 1,775 new cars and rebuilt 3,000; by 1992 the entire fleet of 5,900 cars will be new or rebuilt. Better than 90 percent of the fleet is now air-conditioned (compared with 35 percent 10 years ago). The war on graffiti was declared won in May 1989; cars are virtually graffiti-free, though many of the stations are still so adorned. But, Cianciotti says, "people who were riding the subways weren't always aware of the changes. You'd get on a train and see no graffiti and say, 'I must be lucky.' "

In fact, familiarity clearly breeding contempt, longtime city residents had more hostile attitudes toward the subways than newcomers, surveys showed. In small research "focus" groups, Lender recalls, "people would come in and ventilate. They'd just complain and pound the table... ."

So from the start the effort required a certain psychological insight into disgruntled consumers. ThePhase 1 print and transit ads featured photos of snarly-looking New Yorkers of 1982 remarking on various aspects of the bad old days, then noted the subway's improvements. "People in New York always complain," Lender reasons. "The Mets never win enough. Life is always worse than it ought to be."

After eight weeks of advertising last fall, ridership was up 1.7 percent. Surveys showed that the proportion of riders who said the subway had improved "a lot" in the past two years had climbed to a non-whopping but still better-than-one-might-think 17 percent. "There's limited gratitude on the part of everyone for receiving this information," says Lender, "but it did what it was supposed to do."

It's too soon to tell whether Phase 2, the TV campaign, will be equally effective, but what it is supposed to do is create "perceptual shifts" that are "a necessary prelude to reversing behavioral patterns." Translation: Now that you know the subway system is improving, maybe we can get you to bad-mouth it less. To ride it more. "To realize there's beauty in it, there's grit in it, there's intensity," says Lender, nearly poetically.

Trouble is, the beauty is sort of a metaphysical concept, whereas the grit and intensity jump right out at you. Despite the cooler cars, for instance, temperatures on the platforms regularly edge toward triple digits this time of year. The cars are mostly new or rebuilt, but only 50 of the 469 stations have been renovated since 1984.

Crime in the subways, as in the rest of the city, is climbing. It doesn't account for as high a proportion of the city's total crime as New Yorkers think (just 3 percent), and transit officials bellyache about subway crimes getting more tabloid ink than street crime, but it's high enough to give riders the willies: more than 1,500 felonies in May, up 18 percent from last May. Robberies up 29 percent. But ejections by the Transit Authority Police, their ranks reduced by fiscal woes, down by nearly a quarter for the first five months of this year. Summonses issued, down by 20 percent.

"Operation Enforcement," an attempt to sweep the disruptive, the homeless and the panhandlers from stations and trains, launched last fall with considerable fanfare, no longer officially exists. A Transit Authority spokesman says that TA police and social workers continue "trying to gain control a line at a time."

Meanwhile, the region's general economic malaise, and fare-beating that's reached the equivalent of 200,000 nonpaying riders per average weekday, have brought paying ridership down month by month. May's ridership -- 3.3 million on an average weekday -- was nearly 6 percent less than the May '89 figure.

Arrayed against such real, not merely perceptual, problems, even a campaign expected to reach 95 percent of New Yorkers by broadcast and cable TV (with heavy buys during Mets and Yankees games) has, let's say, limitations. New York's is the world's largest subway system; upstarts like Washington's Metro, with a mere 61 stations and only 516,000 trips taken per weekday, aren't remotely in the same league.

So Phase 3 of the subways campaign, to commence next year, will try still another incentive. It will appeal to New Yorkers' sense of civic duty, rallying riders to support the city by supporting its transit system. But it also will adopt the local attitude, the inverse pride, that makes it gauche to stare up at skyscrapers or consider living someplace pleasant, like Tallahassee. In short, Bergelt Litchfield is going to try to make it uncool to hail a cab.

The ads will reflect the conviction that "you can't be a true New Yorker and not use the subway," Cianciotti says. It's a nicely nervy concept: Are you gritty and intense enough to ride the F train, or are you (sneer) some kinda tourist? "Tap into that sense of pride," says Cianciotti. "New Yorkers always know the right restaurant, the right everything, the best deal... . The subways are a great deal."

Shortly after saying so, Cianciotti left Bergelt Litchfield for Ketchum Advertising, a much bigger uptown agency that handles the French's Mustard account, a couple of big banks, Wheatena and the French Government Tourist Office. The easy stuff.