The Rev. Thomas Brown, a 30-year resident of the predominantly black community of Gum Springs near Mount Vernon, remembers when having a converted boxcar for a home was a luxury.

Brown, now 58, shared the three-room boxcar with his wife and six children for 10 years until they were able to buy a home elsewhere in Gum Springs. The boxcar, which once housed railroad crewmen, was on the site of the recently built Brosar Park housing development. Several other families lived on the land, mostly in small shacks.

"Owning three rooms, to me, was a boon," said Brown, president of the Gum Springs Civic Association, reminiscing last week about the home he obtained free from the Southern Railway Co. in 1952. "It was nice and snug and compact, and later we air conditioned it, . . . had the only air-conditioned shack down there."

Today in Gum Springs the shacks, outhouses and weeds are gone, replaced by neat rows of new houses along paved streets. With the houses have come sidewalks, storm sewers, lighting, a community center and new health facilities, built with the help of Fairfax County and the federal government. But community leaders say there still is much to be done--20 per cent of the homes need substantial repair--and expressed concern that federal budget cutting could threaten several community programs.

Awaiting approval by the federal Department of Housing and Urban Development is the 105-unit West Ford town house development, which has run into opposition from some residents of surrounding developments. Gum Springs residents claim the opposition is racially motivated, but their neighbors say they are concerned about the cost of building subdized housing and claim the project would serve low-income outsiders rather than Gum Springs residents.

Until the early 1960s, Gum Springs was made up primarily of wooden shacks and dirt roads; it lacked sewers and running water. An historic community of 3,200 people, Gum Springs is six miles from Washington along U.S. Rte. 1, in the midst of one of the nation's most affluent counties. In 1966, the community was the first in the country to receive federal anti-poverty funds.

Despite the gains of the past several years, the worsening economy and cuts in a number of the programs on which the community has depended are taking their toll on Gum Springs, community leaders say.

The Saunders B. Moon Community Action Association and the Saunders B. Moon Housing Development Corp., two organizations that have fought for Gum Springs improvement programs, expect to have fewer federal funds in the coming year. Calvin L. Ferguson, director of the Community Action Association, estimates that the group, which serves Gum Springs as well as surrounding areas, will lose close to $75,000, or 25 to 30 percent of its funds.

The association already has discontinued one of its programs, said Ed Gadsden, assistant to the association's deputy director. The program, designed to help ex-convicts find employment and readjust after their release from jail, ended last month after funds from the Department of Labor were cut.

Stricter eligibility requirements for low-income families who receive federal aid for their children's day care may prevent some families from taking advantage of the community center's Child Development Center, acting director Sebastian Ziraba said. Kaye Kory, director of the association's Senior Center, which provides various services for senior citizens, said she has been notified that the center's nutrition program is in danger.

Ferguson estimates that the unemployment rate in Gum Springs is about 25 percent. But Brown has noticed a change in the employment rate since he came to the area about 30 years ago.

"I don't feel unemployment is as drastic in Gum Springs as it was when I came," he said.

The Housing Development Corporation's funds have been reduced by more than 50 percent, said executive director Kay Holland. She declined to give specific figures.

"We hope to continue to exist in some form or other," she said. "There's a possibility of letting staff go, just to exist, or cutting back on certain services."

Community leaders say it is too early to tell what the full impact of cuts in federal programs on the community will be. But the directors of the Community Action Association and the HDC have decided to turn to private private organizations and businesses for assistance.

The association and Anheuser-Busch Inc. will set up an aluminum recycling center, which will help keep the community clean and offer employment to local youth, Gadsden said.

The HDC's counseling service, which serves all of Northern Virginia, aids people who are homeless or have other housing problems. Holland said the number of people seeking help because they have lost their jobs and cannot make mortgage or rent payments has tripled in the past year.

"In the past six months, it seems to be getting worse every day," she said.

President Reagan's veto last month of a housing aid bill, which would have subsidized mortgage interest rates up to 4 percent for moderate-income families, was a disappointment to the residents of Gum Springs, many of whom would have been aided by the measure, Holland said.

Housing has long been a problem in Gum Springs, but in the past two decades the community has been able to improve the situation with the construction of the Spring Garden Apartments, which in the 1960s provided housing for many whose homes were condemned, and the Gabriel Plaza and Brosar Park subdivisions. With the completion of the planned 105-unit West Ford town house development, Holland said, the housing situation in Gum Springs will be "stable."

The $6 million development, approved last April by the county Board of Supervisors, will be built by the county's housing authority with HUD funds. The project is named for West Ford, a freed slave who in 1832 purchased the Gum Springs land. The county is now waiting for HUD to approve its development plans before beginning work on the project, Fairfax Housing and Community Development spokeswoman Virginia Johnson said last week.

Some residents of surrounding communities who are opposed to the project took the issue to U.S. Rep. Stanford Parris (R-Va.), who wrote to his constituents asking for their opinions. Parris said last week that he received between 4,500 and 5,000 responses, of which 80 percent indicated opposition to the proposed development.

Parris' letter, which stated that the Gum Springs-Hybla Valley area is "one of the most highly concentrated areas of federally assisted multi-family housing in Fairfax County," drew a detailed response from Mount Vernon District Supervisor Sandra L. Duckworth. The supervisor, who supports the West Ford project, said the Mount Vernon district has only 2.23 percent of the county's 22,011 publicly assisted housing units.

Gum Springs leaders say they are angered by the opposition to the West Ford project, which would offer better housing to residents still living in substandard dwellings and would allow former residents to return to the area. Civic leader Brown described those who wish to block the project as "a handful of whites who've just moved in about two years ago" and do not know or care about the community's history or concerns.

Brown criticized Parris for his willingness to listen to those who oppose the West Ford project.

"He has made no research at all as to what West Ford is all about," Brown said.

Parris said last week he has taken no position for or against the project, and is only trying to address his constituents' concerns.

For other Gum Springs housing projects, there has been a long road to completion.

Brosar Park, 37 homes for low- and moderate-income families, got its start in 1968 when the people who owned the land sold it to the county's housing authority, which worked closely with them to plan and develop the project. In the early 1970s, the Nixon administration put a freeze on the low-income housing programs that would have helped fund Brosar Park construction. In 1977, with the help of the HDC, residents obtained a federal Community Development Block Grant that allowed work on Brosar Park to continue.

Meanwhile, developers were eager to build shopping centers and other commercial projects along Rte. 1, which would have threatened the residential character of Gums Springs. Residents successfully fought a number of proposals, and in 1979 succeeded in getting the county to designate their community a conservation area. This removed much of the danger of commercial development without approval of community residents, Holland said.

Even so, commercial development remains a concern, Community Action Association Director Calvin L. Ferguson said. Near the entrance to the community on Sherwood Hall Lane, large "For Sale" signs on two tracts advertise that the land is zoned for commercial use.