In the midst of Burke Center, a new town rising in the vanishing rural reaches of southern Fairfax County, will be the remnants of a farm - an old homestead with clapboard siding, wooden steps leading up to a front porch, and a big brick fireplace.

The homestead was built in 1882, converted to a roadhouse during Prohibition, and over the years the nearby barn was burned to its foundation, according to the farm's history.

Although this account sounds perfectly likely, it is total fiction, a "story line" conceived by West Coast architect hired to fashion an image for Fairfax County's newest town. Both the "95-year-old farmhouse" and the barn's rubble foundation will have to be constructed from stratch, just like everything else in Burke Centre.

Burke Centre, where construction began about five months ago and houses are being bought before they're built, is a new town that will eventually contain 15,000 residents in a deliberately contrived country atmosphere.

Where the first section of Fairfax County's classic new town, Reston, was centered around an urban plaza dominated by a high-rise apartment building, Burke Centre's first section will be clustered around the newly constructed "old farmhouse."

For all the thought going into creating its history, Burke Centre is, in many respects, a movement away from the new towns of the late 1960s. It has none of the grandiose objectives associated with the new town movement.

Five builders in Burke Centre all report some 100 houses under construction are selling rapidly, well ahead of schedule. But the place's initial popularity seems to have little to do with the dream that got so many new towns started. This was the dream of creating unabashed urban communities in the countryside, with a yeasty, but carefully designed, mix of residential, commercial and industrial uses that was supposed to provide the advantages of both city and suburban living, with a minimum of the problems.

People who plan to move to Burke Centre say they are attracted by another dream, not as ambitious but apparently more abiding - owning a detached house on an individual lot. Houses in Burke Centre cost between $55,000 and $85,000, in contrast to Reston, where virtually all single-family detached homes now cost more than $70,000.

"We bought a house, not an area," Harriet Damelin said. Mrs. Damelin and her husband, Harold, will move into a house in the Twin Lakes cluster of Burke Centre's first community, the Ponds, in May.

"I don't have strong feelings about Burke Centre," Mrs. Damelin said. "Anyone that they can't be fulfilled."

"Burke Centre as a planned community does not mean that much to us," home buyer Marilyn Weary said. "It's just a little supplement."

While the Damelins and Wearys are typical of the home buyers who will begin moving into Burke Centre late this spring, they are not at all typical of the people who were supposed to populate new towns as they were conceived.

The mood at the time, the late 1960s, was recalled by Reston's chief planner, Francis G. Steinbauer:

"There was a lot of heady, dreamy, euphoric feeling about new towns," he said. "It had to do with the ever-increasing expectations people had about everything. But now those expectations have peaked out. People have gone conservative on everything. They are swinging back to the single-family home."

Steinbauer thinks that trend will mean a "wasteful use of land" and he is confident the pendulum will swing back to more compact development, even high-rises. But right now people want single-family houses - and they are finding them in Burke Centre.

In fact, all the development so far is detached single-family houses. The town houses will come later during the next few years. There will be apartments, but so far fewer proportionately than in Reston or other new towns. There will be no high-rise dominating the landscape such as Heron House in Reston's first village of Lake Anne. And there will be only a fraction of the industrial development existing or planned for Reston.

Though Burke Centre will not have the mixture of residential, commercial and industrial uses that was supposed to be the identifying feature of new towns, planner Edward M. Risse and consultant Wayne Williams maintain it will not be just another subdivision, on a larger scale.

Risse noted that in the second phase of construction in the Ponds community, the streets will be private to avoid standards set by Fairfax's subdivision control ordinance. Risse said the standards, which call for wide, paved roads, impose a monotonous perspective, requiring extensive clearing of trees and leveling of land.

Though single-family detached houses are being emphasized in initial development, Risse said that later they will be clustered to create a broad ribbon of open space on either side of the roads.

Williams thinks the recreation and community centers, which will have spaces that aren't earmarked for specific functions, will provide a place for what he calls "semibusinesses . . . for people in the twilight zone between avocation and I'm going into my own business.'"

Williams says he sees such places becoming bazaars where residents will sell such things as pottery, jewelry, flowers and other handicrafts.

If that happens, he says, Burke Centre will be ahead of Reston, where the two shopping centers have largely failed to become the bustling village centers that planners envisioned.Many stores have gone out of business, and space has gone unrented for months.

Burke Centre, however, is not without its critics. "Burke Centre is a total disaster as far as transportation is concerned," John F. Herrity, chairman of the Fairfax Board of Supervisors, said. When he was supervisor for the Springfield district, which covers Burke Centre, Herrity opposed the rezoning, permitting creation of a new town.

Herrity wanted more land set aside for industrial uses in the town roughly bounded by the Southern Railway, Rte. 123, Lee Chapel and Burke Lake Roads. Industry and the smaller residential base, he said, would have put less demand on the narrow, winding country roads leading to Burke and on other public services, such as schools.

Burke Centre not only got its rezoning, but last month the supervisors voted, 4 to 2, to enlarge it by 80 acres, which will mean more than 400 additional houses and apartments.

When what is now Burke Centre was first considered as a population center, two major expressways were planned for the area, but both of those ideas have been scrapped.

A major road will extend diagonally through the new town, but will empty at either end into already overburdened two-lane roads, which won't be widened for some years.

The outlook for other public services is no more sanguine, but zoning attorney John T. Hazel Jr., one of the partners in developing Burke Centre, is confident that they will be expanded or added as the new town grows.

He points out that Burke Centre is "shirttailing" on other development in the area, arguing that growth pressures from throughout the area will keep public services on schedule.

Mrs. Damelin, who will be one of the first residents of the new town, is not at all apprehensive.

"I live in West Springfield," she said. I feel we're not going into any more congestion than we're leaving.