Tomorrow is the ceremonial opening of the Addison Road Metro subway station and the city fathers of adjoining Seat Pleasant are planning to celebrate. What they are celebrating, however, is the election of a new mayor -- an occasion that will be marked by a semi-formal inaugural ball tomorrow night.

No town officials will join Maryland Gov. Harry Hughes, D.C. Mayor Marion Barry or any of the other dignitaries in speaking at the subway ceremony. And, in contrast to nearby Capitol Heights, which plans to plant a tree and cosponsor a luncheon in honor of its new Metro stop, Seat Pleasant officials plan to be only passive participants in the whole subway celebration.

"There are more important critical concerns for city funds than an opening ceremony," sniffed Eddie Tobias, the Seat Pleasant city administrator.

The magic of Metro has so far failed to sweep this frayed corner of suburbia that, according to what the municipality said in an application for federal anticrime funds, "suffers all the urban ills found in larger aging Northeast cities."

While other areas adjacent to Metro are enjoying or looking forward to a renaissance, Seat Pleasant worries about an unemployment rate three times the Prince George's county average, rundown and abandoned houses and a high crime rate to boot. Its many middle-class citizens and city officials have been working hard to overcome such obvious obstacles to outside investment. It has not been easy.

"The area has a generally negative image -- one of high crime and deterioration," said a county consultant, explaining in a recent report why at least for the next five years Metro-related "growth is both perceived and projected as being very limited here."

Commercial development, rampant land speculation, more business, more jobs and a higher tax base to help cure those ills -- that promised land of subway-spurred prosperity -- are but distant visions of an indefinite future. Earlier talk of a new Rosslyn has faded; land records show that little property has changed hands. And, so many residents, including potential subway riders, Metro means more car congestion, and maybe more crime.

To combat the former, the city of Seat Pleasant is posting three-hour parking signs, from which residents are exempted for $1 a year. In the unincorporated subdivisions south of Metro's 482-space parking lot, the county is considering placing temporary two-hour parking signs and, early next year, adopting a similar resident parking program.

To Myrna Watkins, director of Another Way, a youth counseling center, the sleek new Metro terminal "could be a new haven for delinquency, hanging out." She is hoping to use posters of Powerhouse, a sinewy cartoon creation of an area teenager, to ward off vandalism and graffiti there.

The new station, for now the eastern end of the Blue Line, sits across Central Avenue from a small shopping center. Its merchants are unimpressed by the projections of up to 22,000 daily riders.

To Paul Beall, who is renovating one portion of the shopping center for his liquor store currently located up the block, Metro "could be more of a liability than an asset. I'm gonna make a lot of enemies with these (parked commuter) cars I'll have to tow away. I'll be content to keep what (business) I have."

The coming of Metro is what prompted Rosalind Harrison to open the Central Avenue Crab House (Seasoned right, and dynomite") here eight years ago, but she says now she is looking for "only a small percentage" increase in business from the subway. "With inflation and the economy," she said, "I don't think Metro's gonna do what people think it will do on this avenue."

Central Avenue, city and county officials agree, could be the key to the success or failure of Seat Pleasant's renewal efforts. There has been talk of, but no money for, a pedestrian bridge linking the station and the shopping center. Without it, county planners warn, commuters won't cross the heavily traveled divided highway to spend their money.

The avenue, an extension of East Capitol Street, is being widened from two to six lanes inside the Beltway to help speed more than half the subway riders commuting by car and bus from outlying areas to the east. Instead of expanding outward along the avenue -- the traditional pattern of suburban growth -- development is creeping inward from the Beltway, filling up some of the last remaining rural land near the District with light industry and office buildings.

And on the farmland that sits incongruously amid all the development are the signposts of change that say things like "27 Acres, Zoned Shopping Center and Office Building." The question facing Seat Pleasant is whether the growth will stop at its city line.

City officials are hoping it won't, and they have turned to the federal government for financial and technical help. Their most ambitious plan is to acquire and market a 15.1-acre site which they hope will bring job-generating offices and industry. Safeway has been courting the city for four years for a piece of the corner. A Safeway official said the city had been largely unresponsive, clinging to a plan for light industry that consultants suggested was unrealistic. City officials now promise a new receptivity to the supermarket chain for at least part of the tract.

The parcel in question, some of it already city-owned, is now strewn with rubble and occupied in part by an old railroad roundhouse that is a gathering place for wings and drifters. The building is a faint echo of Seat Pleasant's past.

Before it incorporated in 1931, the town of tiny cottages was known as Chesapeake Junction, the transportation hub for Bay-bound vacationers who transferred here from a District trolley line to the Chesapeake Beach Railway. The Washington, Baltimore & Annapolis interurban trolley also passed through, along what was known as Railroad Avenue.

At the beginning of World War II, the road was known as "the worst entrance into the District" was upgraded to become the George Palmer Highway. In those days the town's commercial center was there, a mile away from the intersection of Addison Road and Central Avenue.

There are few survivors from that earlier era, stores or people. A decade ago, white flight took hold. The community which was once predominantly white became 90 percent black, and many of the newcomers were poor. Its shopping district declined, and so did the town's image.

Now, for every step forward, it seems, there is a new threat. Townspeople cheered when the wrecker's ball began the other week to demolish Baber Village, a failed subsidized housing project just east of the city limits. But city officials were soon chagrined to learn that the federal government wants to fill another abandoned housing project on Palmer Highway with poor people.

They were also upset over the new census figures, showing the city's population had dropped during the last decade from 7,212 to 5,101, thereby reducing Seat Pleasant's slice of revenue-sharing funds.

Despite such setbacks, the Seat Pleasant citizens push on. Mayor Frank J. Blackwell, a Defense Department analyst, acknowledges the problems of the present but speaks hopefully of the future. "The biggest thing that has happened to us has been Metro," said Blackwell, even while down-playing its immediate impact.

Even those who are seeking to speculate have been discouraged, he noted, by the somewhat settled nature of the community. Walter Velona, for one, sent out 400 cards soliciting sales earlier this year and found few willing to move. o

"It was amazing," said Velona, a real estate broker who said he represented a group of investors. "People just didn't want to sell their homes, even for three or four times the market price. They just want to stay there."

For those who don't, there is at least the chance that Metro will make a difference. So it was that Elijah L. and Jolana Dillon, who are moving back to his native North Carolina, placed a "For Sale" sign on their chain-link fence the other day with high hopes.

Somewhat aghast at the $58,900 price tag they put on their three bedroom, asbestos-shingled home within sight of the new subway station, Jolana Dillon said, "We weren't gonna give it away because everthing around a Metro stop is supposed to be worth something."