It was a sizzling performance of Talley Beatty's "The Stack-Up" that brought the evening at Wolf Trap to a climax Tuesday night, as the Alvin Ailey American Dance Theater concluded the second of three programs slated for Filene Center.

This was the old-time Ailey excitement that brings crowds to their feet shouting, stirred to the gut by the sight of impeccably disciplined dancers streaking, spinning, flexing and flying across the stage.

"The Stack-Up" dates from 1982, but it is of a piece with a whole series of dances Beatty has staged for Ailey since the '60s, mostly studies of a particular social milieu. In this case it is city streets and urban night life, fraught with danger, violence, the bravado of the young, erotic stimuli and the deadly lure of drugs. The scene and the theme have been addressed choreographically many times. What gives "The Stack-Up" its charged impact despite the almost trite material is Beatty's sure command of the jazz dance idiom, along with an exceptional compositional skill. The piece starts at a feverish pitch, yet somehow never lets down; the currents rise and fall, but the overall feeling of crescendo persists to the last.

To a pulsating disco score from such sources as Earth, Wind and Fire and the Fearless Four, Beatty sets up a simple dramatic skeleton -- a cynical pusher as the nemesis of a pair of idealistic young lovers. Surrounding the trio of principals are the denizens of the nocturnal ghetto: gang toughs, tarts, fancy dans, passing innocents. The decor, based partly on a Romare Bearden painting, the florid costumes by Carol Vollet Garner and Tom Skelton's feverish lighting furnish the ambiance. The rest of the effect comes from the brilliant dancing of the Ailey ensemble, numbering 17 in this work, and particularly the electric characterizations by Gary DeLoatch as the pusher, and Ralph Glenmore and Marilyn Banks as the lovers.

The evening also saw the premiere of a new production of Louis Johnson's "Lament," out of the Ailey repertory for a dozen years. In 1953, it was Johnson's first professional choreography. However it appeared then, it looks now like youthful excess, and an odd choice for revival.

The main portion is a jungle ritual involving men in silver loincloths, women in tasseled waists and a black-cloaked, white-maned Death-Devil figure; the whole thing looks like a relic from Hollywood's seamier dustbins. The music for this part consists of Villa-Lobos chestnuts. Johnson has now added a prologue to pop music, depicting a young couple on a date, entering a theater and sitting down, only to be whisked off stage as the jungle stuff commences. Perhaps this was intended as a whimsical framing device, a wink at the schlockiness of the ensuing melodrama, but it just seems out of key. The strong performance by a crew of 12 was wasted on the choreography, a mixture of slam-bang gymnastics and ballet-jazz-modern eclecticism.

Which brings us to the perplexing "How to Walk an Elephant," the new work Ailey commissioned from collaborators Bill T. Jones and Arnie Zane, which had its world premiere Monday evening and was repeated on this program. On second viewing, the work still seems overburdened with movement motifs and obscure references, unsatifyingly structured in fits and starts, and unclear as a statement.

On the other hand, Jones and Zane are not only extremely deft craftsmen -- a fact much evident in "Elephant" whatever its flaws -- but also unusually inventive and thoughtful artists. As a team -- one black and one white, both cannily perceptive about the racist and sexist undertones of the dance past -- they repesent just the kind of challenge Ailey wisely seeks out, one that can stretch his dancers, his audience, the critics and the choreographers themselves.

At second sight, some light also begins to break about the work's wry allusions to Balanchine's "Serenade." A possible scenario: The elephant stands for the huge, lumbering classical ballet establishment (recall that Balanchine once literally choreographed circus elephants for Barnum & Bailey), with its virginal ballerinas and slavishly supportive males. Sure, we all love the ballet, but it's really not of our time, so we've got to teach it to walk, that is, to accustom it to the pedestrian movement and contemporary sensibilities that are the stock in trade of postmodernism. Interpretations such as this don't cancel out the shortcomings of "Elephant" as a stage work, but they may help explain its oddball fascination.