"City of Angels," Steven Bochco's much-promoted new hospital drama, showed a pulse with audiences in its debut Sunday night, raising hopes that one of television's oldest and most persistent color barriers may finally be coming down.

The new CBS series performed capably, though not spectacularly, in the national Nielsen ratings, attracting 13.8 million viewers. That ranked "City" 32nd overall for the week, and third in its first half-hour, behind "Who Wants to Be a Millionaire" (28.6 million) on ABC and "Malcolm in the Middle" (23.4 million) on Fox. It also finished third in its second half-hour (behind "Millionaire" and Fox's "X-Files").

Few TV shows of recent memory have had as much riding on them as "City of Angels." In addition to having Bochco's halo around it, the series became something of a sociocultural milepost because it stars a predominantly African American cast.

By television standards, that makes "City" bold and daring. While black sitcoms have had mainstream (that is, white) acceptance for decades, the few black dramas that have been tried on network TV have failed to find a broad enough audience to survive. In fact, other than mixed ensemble shows like Bochco's "Hill Street Blues" and "NYPD Blue," no black drama series has ever made it past its second season. The casualties include "South Central," "413 Hope Street," "Under One Roof" and "Hawk."

The stakes surrounding "City" grew still higher last summer when the NAACP and other civil rights groups challenged the networks over the scarcity of minority actors in their new fall shows. CBS had agreed to carry Bochco's show as a mid-season replacement, months before those protests began.

Bochco said yesterday he was generally pleased with the show's initial reception, considering that the competition also included the season premiere of "The Sopranos" on HBO. He and CBS chief Leslie Moonves said they were confident that "City of Angels" would perform better tonight, when it settles into its regular day and time period, at 8 p.m.

"City" will have time to build since CBS has given it a nearly unheard-of 13-episode commitment. To become a hit, or even merely to survive, it will need to attract large numbers of white viewers as well as black (the network's top researcher, David Poltrack, said figures on the racial composition of the first episode's audience won't be available until later today).

The show will also have to overcome reviews that ran the gamut from savage to weakly laudatory. Several critics found the basic story--failing inner-city hospital staffed by dedicated doctors, scheming administrators and corrupt politicos--flat, slow and ordinary, particularly in light of Bochco's track record.

And to some extent, Bochco agrees.

"In hindsight, I wish we had had a better story in the first episode," he said yesterday. "If that had been Episode 6 or Episode 8, no one would have said boo. I think I was too concerned with being mainstream, if you will. I think we lost some edginess. I was a little nervous about being controversial at the story level, so I went for safer storytelling. That was probably a mistake.

"I don't mean to sound like I'm bagging on the show," he added. "I'm not. It's a fine piece of work, and it gets better. . . . But I'm looking at it through the eyes of the media, which built up a lot of expectations. Everyone was expecting another 'Hill Street Blues' or 'NYPD Blue' that would amaze them."

Moonves said "City" could become a catalyst for more of its kind. "TV programmers are in a lot of ways copycats," he said. "Look at 'Millionaire' " and all its network clones. "But I don't think this is the be-all and end-all" for black dramas. "If Jackie Robinson had failed, there would have been [other] black athletes in baseball. It just would have taken longer."

While it may seem anachronistic to be talking about "color lines" in the 21st century, Robert Thompson, a professor of film and television at Syracuse University, said it pays to bear in mind that television has always been slow to reflect social progress.

"People always talk about how television sets the social agenda," he says. "They've got it backward. Everyone else in society pushes the envelope and TV sits around for five or six years waiting to see if it's safe to come out. When you have to appeal to so many people at once, the ability to do anything progressive is really, really difficult."

Hence, he says, the first dramatic series about the Vietnam War ("Tour of Duty") doesn't appear until the war is over for 12 years; the first lesbian star with a TV series ("Ellen") doesn't reveal her--and her character's--sexuality until 1997.

And it's taken until 2000 for a network to offer a black hospital drama.

Says Bochco: "It would be naive to do a show like this and not locate certain racial tensions. That said, our focus is on melodrama. We'll live or die not by racial dynamics but by how good our storytelling is. Period."

CAPTION: Blair Underwood plays the chief of surgery in CBS's "City of Angels."