IMAGINE YOURSELF in the grocery store. You wrestle a crippled cart from the rack and begin to cruise the crowded aisles. Past the rows of plastic-cased and winter-pallid tomatoes. Past the factory-squared cheeses. On to the rectangles of frozen fish and, if you're lucky, the deli department, where you debate the relative merits of coleslaw and potato salad.

Now imagine a supermarket where you can discuss the merits of various double-cream cheeses with an expert, select a rainbow trout so fresh it's still swimming in a tank or ask the deli manager to make up your own basil chicken recipe for a dinner party. That idealized future is here in half a dozen experimental stores run by Washington's supermarket chains.

Pushing out motor oil and greeting cards, these stores have made room for health foods, prime cuts of meat, fresh seafood, game, coffee beans, dozens of kinds of cheeses and large wine and beer departments. Customers can also shop in expanded ethnic and gourmet food sections. "I want to make it easy for someone to do ethnic meals without going to five little shops to get the ingredients," says Ann Brody, food coordinator for Someplace Special: Giant Gourmet in McLean.

The Giant store is only the latest in the string of special stores opened by area supermarket chains. Farmers Market (a Safeway store in Fairfax) and the two Grand Union Food Markets, one in Rockville and the other in Alexandria, have all opened within the past 15 months. Only Safeway International, which opened in the '60s, has been around a while--first on F Street in the District and now in McLean.

Besides offering greater variety and better-quality food, the stores give more personalized service, moving away from the image of super- See SUPERMARKETS, L2, Col. 5 THE SUPERMARKETS SUPERMARKETS, From L1 markets as unfriendly, antiseptic spaces where shoppers cruise mutely up and down the aisles. "Our stores have become neighborhood gathering places," says Gary Perino, Grand Union's public relations manager. To add to the illusion, Grand Union offers complimentary coffee. More important, it has full-service meat, fish, cheese and health food counters staffed with specially trained people. Customers seem to like the attention. "It's nice to deal with people instead of plastic packaging," said one woman.

Unlike the average supermarket, the special stores can order merchandise requested by customers. The manager at my local Safeway rubuffed a request for Breyer's coffee ice cream, saying he was limited to the flavors provided by the "authorized vendor." No such restrictions hamper Eva Krebs, Safeway International's gourmet foods manager. Working with 17 distributors, she has succeeded in procuring everything from spruce tree honey to hazelnut oil. The store's policy is, "If the customer wants it, we'll get it."

The convenience of being able to add gourmet foods and other special items to the weekly grocery list is undeniable. Not only are the supermarket prices for these goods generally competitive, but in every store except Farmers Market, one can buy standard items such as orange juice or potato chips for the same prices offered by that chain's regular stores. (Though Farmers Market has a policy of pricing produce, dairy products, beer and wine lower than other Safeways, it charges more for many other items.)

The extra service and superior merchandise in the special stores are such an improvement over the supermarkets to which we are accustomed that it seems almost in bad taste to mention any deficiencies. There are several, however.

First, the ethnic food sections are generally disappointing in variety and quantity of goods; these items are likely to be better bought at the ethnic grocery stores and delis scattered through the city. Produce is blessedly free of cellophane wrappings, but in some cases is not fresher or more varied than in regular supermarkets. And despite the admirable diversity in cheeses, many consumers would prefer to buy it cut to order rather than in the prepackaged form found in most of the stores.

Whether the experimental stores remain isolated showpieces or proliferate throughout the area depends largely on their profitability to the chains. So far all are in prosperous suburbs, earning them the label of "upscale stores." Both Giant's Someplace Special and nearby Safeway International were sited carefully for easy accessibility by Washington VIPs and McLean's well-educated, high-income populace, acknowledge supermarket officials. Despite the location of Grand Union's stores in similar communities, however, Vice President Donald Vaillancourt says, "We are not seeking just the affluent customer, but all kinds of people."

Safeway International has performed well through the years, but the more recently opened Farmers Market has not been a high-volume store and the company has no immediate plans to open others on that model. Barry Scher, public relations manager for Giant, describes business at Someplace Special during its first month as "phenomenal," but adds that it's too early to say whether other stores are in the offing.

Grand Union, on the other hand, plans to develop its Food Markets "aggressively" in the Washington area, according to Vaillancourt. With about 80 of these stores already operating across the country, the company has vowed to spend $700 million over the next six years to build and renovate others using that format. Its research shows that the typical customer will drive an average of 1.5 miles to a regular supermarket, but up to 10 miles to a Food Market. The increased sales volume enables the Food Markets to cover their higher operating costs, says Vaillancourt.