Catherine Sommerville still lives only a few blocks from the old brown stucco house on Russell Avenue where she grew up and where her younger sister was born. But now she tries to stay away from her childhood neighborhood near old downtown Gaithersburg.

"I avoid that street as much as possible," she said recently. "It's sickening to see what's happened to that home where my mother slaved to keep everything neat."

Eleven years ago, and for decades before that, the 200 feet of lawns Diamond Avenue to Brookes Avenue made up "the prettiest block in all of Gaithersburg," Sommerville said. Now all that is gone.

The home that belonged to Sommerville's parents has been a rooming house for the past few years; the buildings on either side of it have been torn down. Further up the block, a washing machine and a rusted, rotting chair grace the porch of an abandoned home.

This one long block of Russell Avenue was left in the backwash of the development boom that swept through the area when Interstate 270 came through.

Once, a decade ago, the town's planners had dreams of transforming the block from a world of tall trees and rambling homes into a sparkling highrise commercial complex.

But then the new suburban developments were started a mile or more away from the old town center, out to the north and west along Montgomery Village Avenue and Quince Orchard Boulevard. And the new stores followed the path of the new homes, and left behind the old town center. Russell Avenue, and the planner's dreams.

A residential area since 1390, that block of Russell Avenue now lives in limbo, the relics of its past crumbling as it waits, uncertainly, for the commmercial development of the future that has not yet begun.

It all started in 1965, when, through the magic of master plans and zoning amendments, two-thirds of the block was zoned for commercial use. At the same time, many of the owners of the large, comfortable homes had grown old, and were reluctant to retire in their large and aging homes.

One development philosophy was prevalent in the town at that time: harness the development pressures and use them to rebuild the old downtown are. Grand new stores and office complexes were to replace the graying old signs and stores of East Diamond Avenue.

It was at that time most of the first block of Russell Avenue, which dead-ended into the main downtown street, was rezoned.

The rezoning helped give 82-year-old Henry Meyer the impetus to sell his home at number 7. The rezoning, and the fact that the frail widower had had "a couple of heart attacks," prompted him, he recalled. The doctor said "I couldn't stay alone in a seven-room house." So he moved to a new subdivision not far from the old downtown.

Kay Bowling, a local real estate agent, bought the Meyer house immediately.At the same time, she bought the old brown stucco house that belonged to Dr. Frank Broschart, Catherine Sommerville's father.

Dr. Broschart, whose wife died shortly after the sale, went to live with his daughter in another new subdivision.

Bowling said recently that she bought those two houses, and the nearby house of Claris and Kirk Griffiths, because "my prime interest was the development of the town in the best interests of the town."

Heading a group of investors, some of them local townspeople. Bowling set out to build the commercial highrise complex she thought would give new sparkle to the old downtown, but she didn't have all the land she needed, and then the money market was getting tight.

The three houses she bought were rented out almost immediately. "I could have torn them down," she said, "but I wouldn't have had the money to make the monthly mortgage payments after they were torn down."

So the rental money went toward the mortgage payments. There wasn't enough left over to pay for repairs as well. The houses deteriorated; two were condemned.

Meanwhile, a new philosophy had taken over among the town's planners. Instead of concentrating new commercial development downtown, near the old main street and on side streets like Russell Avenue, they would relocate Gaithersburg's new commercial center near the mushrooming new suburbs.

By that time, the heart had been taken out of what Russell Avenue was before. "Sometimes I'm almost ashamed of the block," said 21-year-old Bruce Goad, whose parents are the last homeowners who still live on the the section of the block that was rezoned. Four houses are gone, the fifth's for sale, the sixth's a boarding house."

Anger builds in Catherine Sommerville's voice as she talks about he decaying block. "I don't think it would have changed without the rezoning," she said. "Being as Russell Avenue (on the block) is commercial property, they're letting it go.

"There ought to be a law against people buying houses and letting them run down.

Kay Dowling, the real estate agent who helped buy the land to realize her dreams of a commercial complex, greets this vehemence with equanimity.

"Frequently it's necessary to tear down in order to build up," she said. "Whether things are torn down and built up right away or whether they stay torn down for a few years doesn't much matter . . .

"I had hopes in 1966 that is would be developed long before now," she added. And even now, she believes, the development will come soon enough. "In a year or two," she mused calmly. "A year or two."