As the Metro subway system prepares to extend out Connecticut Avenue NW into three new neighborhoods this weekend, there is general -- but not universal -- optimism among the community's residents and merchants about the arrival of the silver trains.

The three new stations that will be open for business on Sunday -- Woodley Park-Zoo, Cleveland Park and Van Ness-UDC, all along Connecticut -- are Metro's first in the generally affluent neighborhoods between the Potomac River and Rock Creek. The Connecticut corridor is predominantly white and is home to thousands of elderly residents.

The new stations will provide access to the University of the District of Columbia, to the National Zoo, to hotels, restaurants and a movie theater. They also will give some downtown workers a chance to forsake their cars in the morning and reach their offices in a matter of minutes.

Months of construction made the corridor a traffic-choked gauntlet that motorists and pedestrians dreaded to run. Now the area will find out whether it was all worth it.

Pamela Davis, an electrical engineering student at UDC, stood at the edge of the school's Van Ness campus on a recent afternoon waiting for her bus. She sees the advent of Metro as a way to cut her commuting time to school in half.

"I live near the Takoma station," the 19-year-old woman explained with a smile. "Now it takes me an hour, but with the subway I can make it in a half an hour."

But Astrik Aznavorian, 77, diminutive and jaunty in a white beret, said she won't use the subway, even though she lives near the Cleveland Park station. "I know the subways of Moscow, of Leningrad, of Paris, of London," she said as she took a special preview tour for senior citizens. "This one I don't like. We retired people have time; we don't have to hurry. We can take the bus."

Blanca Calcagno of the Vace Italian Deli in Cleveland Park said she envisions subway riders emerging from the ground some 35 feet from her store and developing a taste for her Italian sandwiches. "So many people around here are happy about it," she said. "Sure it'll be good for business. Oh, yeah."

Polly Shackleton, Ward 3's veteran representative on the City Council, said the only real squawking from residents along the route came when they were confronted with the possibility that once the trains started running, the frequent bus service up and down Connecticut Avenue might be eliminated. But they made enough noise to change the transit system's plans and retain most of the buses.

No immediate explosion of property values in the vicinity of the stations is anticipated, partly because of the current anemic state of the real estate industry, partly because the area's land values are traditionally high and partly because residents have long known that the trains were coming, thus creating a steadier kind of escalation in land values.

The stations are an extension of the Metro system's Red Line, which currently ends at Dupont Circle. Beginning this weekend, subway riders will be able to go 2.5 miles beyond the circle, zooming beneath Rock Creek to emerge in what amounts to, for Metro, a new world.

The first of the new stations past Dupont Circle is Woodley Park-Zoo, located at Connecticut Avenue and Woodley Road NW. The "free world's longest escalator" -- at 204 feet it surpasses the current longest at Metro's Rosslyn station but is still shorter than one in Leningrad -- and a 10-story elevator will disgorge riders at the doorstep of the 1,500-room Sheraton Washington Hotel, a circumstance that suits the hotel just fine.

"We feel that the Metro is going to bring what we are, an uptown hotel, downtown," said Penny Cummings, Sheraton's spokeswoman. She said the hotel is counting on an economic boom from the fact that guests will be able to take the Metro from National Airport to the hotel, with one transfer at the Metro Center station. That situation also benefits the large Shoreham Hotel a block away.

In addition, Cummings said her hotel hopes to entice the lawyers, lobbyists and accountants who work in the Farragut Square area to hop on a Red Line train and visit the Sheraton for lunch, dinner or a drink after work. "This opens up a whole new world both for people who work downtown and for the merchants in our area," she said.

Several blocks up Connecticut is the entrance to the National Zoo, where officials hope the Metro will help eliminate a massive parking problem. A spokesman said that on summer weekend days, the zoo's 1,000 parking spaces often are filled by 10 a.m., leaving thousands of visitors to prowl the nearby residential streets in search of parking spaces. The situation would improve if some of those visitors arrived by train.

The next new stop, several tree-lined blocks farther up from the zoo -- a bit closer to the zoo, in fact, than the Woodley Park-Zoo station -- is Cleveland Park, an area so named because President Grover Cleveland once maintained a summer home at what is now 35th and Newark streets. Merchants in the small shopping and restaurant strip near the Connecticut Avenue intersection with Porter Street, where the new station is located, hope, like those elsewhere along the route, that Metro will bring new customers.

Conan Gallagher of Gallagher's Pub, a tavern in the 3300 block of Connecticut, said he hopes the subway will bring customers for lunch. There are seven restaurants on his block alone -- Italian, vegetarian, meat-and-potatoes -- and a few others scattered through the Cleveland Park neighborhood.

But Tim Kiernan, manager of the Woodley Flower Shop -- which has anchored the corner of Connecticut and Ordway Street for 31 years -- said he doubts that people will throng from around the city to wine and dine in Cleveland Park.

"The same people who already get off the bus here every day are the people who are going to be riding the Metro," he said. "I don't think the neighborhood has a particular draw, like a major department store, to draw people."

The neighborhood is home to a number of young and middle-aged professionals, who will be able to use the subway to commute to work. But the faction most in evidence on the streets of Cleveland Park is the large elderly population, retirees who live in such complexes as the massive Broadmoor apartments at Connecticut and Quebec Street, or Quebec House just down the street.

In an attempt to convince these elderly residents that they should use the subway, the system's spokesman, Cody Pfanstiehl, last week conducted several tours of the system for senior citizens. On Wednesday, a group of about 100 took him up on the invitation. When it was over, while few seemed to dislike the system, many remained skeptical.

"I doubt many of us will use it," said Bertha Levy, 80. She attributed the wariness to old habits. She said that when she wants to go shopping at Woodward & Lothrop downtown -- a site that could be reached in eight minutes by train -- she will probably continue to take the bus or a taxi. Other seniors complained of the amount of walking necessary to get to the Metro stations, which are spaced much further apart than bus stops, and also said that once inside the stations it is necessary to do more walking than they would like to reach the trains.

The Van Ness-UDC stop will become a terminus of the Red Line, and some residents of the neighborhood, which is also built around a small shopping strip, have expressed fears that commuters will park on their streets to take the subway downtown. But a current complaint -- that UDC students are taking up their parking spaces -- could be alleviated as more students take the subway to classes.

As elsewhere, merchants in the area are bullish on the subway. So are most UDC students interviewed, many of whom live across town and say the subway will drastically cut their commuting time.