From his home near the Inner Harbor, C.J. Welsh has watched with interest the new building that has transformed the downtown area and the renovation that has made his neighborhood one of the most expensive and sought after in the city. But Welsh, a city police officer, takes a skeptical view of the changes brought about by Baltimore's heralded "renaissance."

"I used to live in a $12,000 row house in South Baltimore," said Welsh. "Now I live in a $40,000 town house on Federal Hill, and I haven't moved."

Few cities have tried so long, so hard or so creatively to reverse their declines as Baltimore. The well-chronicled story of its evolution from avoidable stop on the road from Washington to New York to urban showcase has made it perhaps the nation's leading symbol of hope for aging industrial cities. The man most responsible for the changes, Mayor William Donald Schaefer, was recently named the best mayor in America by Esquire magazine.

Yet even as more projects are announced and new buildings take their place in the skyline, nagging questions persist about Baltimore's future and the ultimate success of its efforts. Welsh's observation about his neighborhood goes to the heart of the question. In short, is "the new Baltimore" better off in any fundamental way than the old one?

By many statistical measures the answer is no.

*Despite attempts to lure the middle class back to the city, population has continued to decline, falling 18,075 during the first two years of this decade, according to preliminary census figures.

*An increasing proportion of those who remain in the city are poor. In 1970, 14 percent of the population earned incomes below the poverty line. By 1980, that figure had increased to 18.9 percent. Two out of five city residents, according to 1982 figures, had incomes under $10,000 a year; 13.4 percent had incomes under $5,000.

*While the net number of jobs in the city increased by 10,000 during the 1970s, the number of jobs held by city residents during that period declined by 35,000. Employment cutbacks in the neighboring suburbs -- where some of the largest employers of blue collar workers are located -- resulted in Baltimore residents losing another 17,000 jobs.

Such figures led the author of a recent book, "America's Cities: A Report on the Myth of Urban Renaissance," to name Baltimore one of the nation's five "disaster" cities (along with Newark, Philadelphia, Detroit and St. Louis.) In the book, which was published the same day Esquire came out with its profile of Schaefer, author Michael C.D. MacDonald likened urban renewal projects to "Potemkin village facades" and called Baltimore "troubled but salvageable. . . . a dying Snowbelt factory town."

Schaefer, the city's chief booster, responds profanely, or not at all, to criticism of Baltimore. Instead, he focuses on the city's accomplishments and asserted in a recent interview that "the neighborhoods are strong; industries are staying. [Developer James] Rouse wouldn't have built [Harborplace] if he didn't think there was a future in the city."

The closest Schaefer will come to admitting the city has problems is to stress the importance of reversing the flight of middle-class residents and to admit that the city needs "a new industry." But mostly he interprets any criticism or pessimistic assessment of the city as a personal attack. (Even the flattering Esquire profile described him as "Mayor Annoyed, rhymes with paranoid.")

"The biggest problem in Baltimore is that people won't admit we have severe problems," said one neighborhood activist who didn't want her name used for fear of Schaefer's reaction. Sources of the Problems

There are ready explanations for many of Baltimore's problems: Bethlehem Steel and General Motors, two major employers, are victims of foreign imports; federal cutbacks are responsible for mounting problems of the poor and elderly; courts have refused to order equalized state spending on education, and the Maryland General Assembly has exhibited a growing suburban bias.

The Reagan administration's cuts in urban programs have been particularly harmful. In fiscal 1983, Baltimore received $134 million in federal aid, after averaging $425 million annually over the previous eight years. State aid, some of which is passed on to cities, was cut, too. As a result, in fiscal 1984, combined federal and state aid to the city was $562 million, half what it was two years earlier.

In a 1983 study, two Johns Hopkins University professors, Allen C. Goodman and David L. Puryear, concluded that in recent years "many cities experienced substantial downtown revitalization," and that Baltimore's "has been one of the most spectacularly successful." At the same time, they found, "urban problems became worse in all of these large cities, including Baltimore. In other words, Baltimore is similar to many other large cities: full of contrasts between its successes and its problems."

Increasingly, there is a racial component to discussions of Schaefer's priorities and the city's future. Baltimore is the largest majority black city in the nation (54 percent) without a black mayor, and many believe that Schaefer's easy reelection victory last year over William H. (Billy) Murphy Jr., a black former Circuit Court judge, was as much a rejection of Murphy's shrill, disorganized challenge as it was a reaffirmation of Schaefer's leadership. And with Schaefer considered a likely candidate for governor next year, there is a strong possibility that the next mayor will be black.

Many black critics of Schaefer say there are two Baltimores, separated rigidly by race and class, and they single out Harborplace and the new Baltimore Aquarium as symbols of his misplaced priorities.

When Democratic presidential candidate Walter F. Mondale made a campaign visit here a few days before the election, he dutifully appeared in the Inner Harbor and proclaimed that Baltimore had been transformed from "a city going downhill" into "a city on the move."

But before his arrival, the city's black Interdenominational Ministerial Alliance had urged that the rally be held elsewhere, preferably in a black neighborhood. The Rev. Douglas I. Miles, the group's president, called the harbor development "anathema to the black community. It symbolizes all the injustices the local administration [of Schaefer] has perpetrated on the black community."

Bobby Cheeks, president of the Baltimore Welfare Rights Organization, said the black community has "consciously been left out of the decision making" by Schaefer. He said there has been no vigorous housing code enforcement and that many children suffer from lead poisoning as a result. He also said that few city contracts go to minority firms (in the two most recent quarters, according to the city purchasing office, minority firms were awarded 12 percent and 21 percent of the city's business) and that only 2 percent of the city's corporations are run by blacks.

Most blacks, he said, "have no jobs, and little hope of getting jobs."

The city's unemployment rate, 7.4 percent in August, is nearly one-third higher than the statewide average of 5.2 percent.

While Cheeks sees merit in Schaefer's attempts to get suburbanites to move into the city, bringing with them their high incomes, small families and low social costs, he charged it is being accomplished by displacing poor blacks, who are "intimidated" into being uprooted from neighborhoods to make way for gentrified renewal.

Another official of the welfare rights group, Sharon Garner, complains that there are thousands of persons, most of them mothers and children, waiting for public housing but the mayor "is not trying to rehabilitate buildings, although there are plenty of empty places."

Garner, 42, and her three children live in a three-bedroom apartment on the ninth floor of a West Side public housing high rise, where, she says, "nothing trickles down here but the water through the roof."

Some of the city's economic development, however, has benefited the black community. At Mondawmin Mall, a 120-store black-oriented shopping center revitalized and operated by Harborplace developer Rouse, mall manager Marion C. Wesley said sales are running 7 percent ahead of last year and that only two of the 76 stores in the enclosed portion of the 500,000-square-foot center are vacant.

"Our sales don't reflect a disaster, and we're in the middle of a black community," said Wesley, who said a Metro rail station at the mall, one of nine stops on the city's new eight-mile subway system, is responsible for generating some of the additional business this year.

A display in the mall's lobby boasts that "center cities across America are reawakening socially, culturally and economically." But over a picture of the Inner Harbor, someone has written, "This is wrong."

The city's leading black elected officials praise Schaefer for what he has accomplished but urge him to devote more energy and resources to social issues.

"It's a better city now, in some ways," says state Del. Wendell Phillips. "The mayor has done a lot of good, but the pain and hurt of the have-nots have not really been addressed in meaningful fashion. Large segments of the population feel left out in the shuffle. We need to build a bridge between the Inner Harbor -- he's done a beautiful job there -- and the other Baltimore."

Asked if there are "two Baltimores," Kurt L. Schmoke, the Baltimore city state's attorney and the man regarded as having the best chance of becoming the city's first black mayor, replied: "The answer is not a simple yes or no. Money is being spent by the city, more on social and education programs than on bricks and ortar. A case can be made that the spending in the neighborhoods has not been as efficient as it can be."

According to Schaefer, only 17 percent of the federal urban renewal funds received by the city during his tenure has been spent on the Inner Harbor, while 83 percent has gone to neighborhood rehabilitation.

Yet some blacks see a racial bias in Schaefer's support of gentrification and his insistence that the city must attract middle-class (read white) residents, who pay more in taxes than they cost in services.

Advancing a variation of that argument, Schaefer touched off a controversy last summer when he said that the city should not build more low-cost housing.

Schaefer responded that his remarks were taken out of context, but conceded that it had been his policy for some time to discourage construction of low-cost housing in the city. "I don't want not to help the poor," he said. "We just cannot continue to help all the poor.

"If [state officials] want the city of Baltimore to be the place where all the poor congregate," Schaefer told The Baltimore Sun, "we need special compensation from the state. The poor are here because we provide most of the housing, most of the medical care, most of the counseling for the disadvantaged." The Trickle-Down Effect

One of the city's leading black spokesmen, Rep. Parren J. Mitchell (D-Md.), was so outraged by Schaefer's remarks that he threatened to block all federal aid to the city. "With 40,000 people or more on the waiting list for low-income housing . . . it is unconscionable for him to take that position," Mitchell said.

Mitchell also questioned the trickle-down effect of the downtown renewal: "I'm not sure if the money used for revitalization of the Inner Harbor has any impact" on the city's poor black residents.

Schaefer insists that it has.

He says he will continue to work to retain and expand existing smokestack industries, and will encourage other factories to relocate in the city "if they can be nonpolluters." And he has asked existing industries "to warn us if they are going to leave, to delay to give us time to help them," as he has done recently with Western Electric and Esskay Meats.

But the city is now "service oriented," the mayor says, with its future tied to its ability to attract white-collar, computer-based businesses and tourism.

"Seven hotels are being built at one time. Nothing like that has ever happened here before. Tourists will come only if there is something to do," Schaefer said, ticking off some of the new attractions such as Harborplace, the aquarium and a Six Flags theme park being developed at a one-time power plant in the Inner Harbor.

New taxes that result from construction in the Inner Harbor make the city "able to help the poor," according to Schaefer, who said that homesteading programs, state and federal grants and below-market-rate mortgage money made available by the legislature has resulted in the enovation of "hundreds of houses."

Throughout the downtown, the activity has never been greater. Ubiquitous construction cranes are erecting hotels and office buildings, and the Rouse Co. has begun an addition to Harborplace that will double its size.

More than 2,000 new hotel rooms are under construction, including a Sheraton going up in the shadow of the new Haytt Regency, which already has expansion plans. Long-vacant factories are being converted into loft apartments. Half a dozen office towers will add so much new space that Schaefer is cautioning against overbuilding and two new or refurbished department stores are expected to breathe life into a downtown retail district long ago left for dead in favor of suburban shopping malls.

In contrast, on the industrial east side, empty three- and four-story brick factories, thousands of broken windows and fading signs bearing the names of giants of the old industrial age bear silent witness to the change in American industry.

Recent decisions by Bethlehem Steel and General Motors retained 16,000 jobs, although overall employment at the two firms has declined drastically during the past two decades.

Bethlehem is staking its future on a $1 billion modernization of its remaining facilities at the 3,000-acre Sparrows Point plant, where total employment has slipped from a 1959 peak of 30,000, plus 5,000 at the adjoining shipyard, to 10,600 at the mill and 2,000 at the shipyard. GM modernized its Broening Highway plant to produce vans.

There is concern as well over the future of the port, an economic lifeline since Baltimore was founded. Although cargo handled at the state-operated terminals was up about 25 percent in the first three-quarters of this year, Nissan, which accounted for 60,000 vehicles last year, recently moved its import operation to Norfolk.

Baltimore is a blue-collar, union-label factory town, but "no one is building new factories, and if they are, they are doing it in warm climates and nonunion places. So we must try to keep what we have, help them modernize," says Robert C. Embry Jr., a former Schaefer cabinet member who now is a Baltimore developer and member of the city school board.

Embry, whose widely acclaimed nine years as the city's commissioner of housing and community development led to appointment as assistant secretary of Housing and Urban Development in the Carter administration, believes the city is doing what it must, "going after tourism and economic development."

M. Jay Brodie, who succeeded Embry as housing commissioner and served in that position until leaving this year to become head of Washington's Pennsylvania Avenue Development Corporation, said that "over the last quarter century, Baltimore has helped itself more than any other city in the U.S."

He said that Baltimore has "built more housing units than any American city," resulting in an after-inflation doubling of the downtown tax base.

"All of this," he is quick to add, "has not prevented major problems everywhere." He said "no city has the resources to deal with" a growing number of poor and elderly poor.

"The master answer," according to Brodie, is absorbing some of the city's suburban areas, which the city has not done since 1919. He noted that the Sunbelt cities, with the exception of Atlanta, have the ability to annex.

"With annexation, cities can reach out to change the mix, acquire residents who pay more in taxes than they cost in services," says Brodie. They also bring with them important intangibles, he adds. They form civic associations, join PTAs, lobby the city for improved services. City schools, he said, must get middle-class students. Annexation also can provide valuable land for building a new stadium or attracting industry.

Other answers, Brodie suggested, are increased federal funding and regional cost sharing, the later of which already is being done, in some form, in Minneapolis-St. Paul, Indianapolis-Marion County, Miami-Dade County, and metropolitan Toronto.

"In our lifetime," he predicted, "we will see sharing of noncontroversial services" such as fire and police protection, water and sewerage services. The controversial ones, he said, are housing and schools, "which have racial and class components.

"But not even the best mayor in the country can solve the combination of poverty, illiteracy, crime, drugs. And that's not just an old city problem," Brodie said. "There should be a national policy and commitment" toward addressing those issues."