You can take away the lights, the costumes and the special effects of some musicals and still have a musical. The success of "The Pajama Game" doesn't depend on the latest designer sleepwear, and a state-of-the-art staircase is not mandatory for "Hello, Dolly," although a staircase of some sort is. "A Chorus Line," as we all know, calls for no more than a white line painted on the stage floor.

But if you strip "Starlight Express" of its laser beams and the banks of cumulus clouds that regularly billow across the stage, if you remove the extravagant costumes that make the actors look as much like trains as actors can rightfully expect to look; if you suppress the myriad lights sweeping the ceiling and dusting the stage in throbbing Day-Glo colors, you really don't have much left.

Andrew Lloyd Webber's musical, which opened last night at the Kennedy Center Opera House, is a spectacular nonentity.

You may want to see it because the 24 actors on roller skates, who play a variety of engines and cars, whiz out into the audience on a specially constructed circular runway that Minsky would have admired. You may want to see it for the evocation of the Starlight Express, who, as I understand it, is the Great Locomotive in the Sky and the source of the faith that moves mountains. You may want to see it just for the look -- a marriage of comic book and high tech -- that designers John Napier, Rick Belzer and Ted Mather have imparted to matters. Other reasons are harder to come by.

Actually, no one wants to move mountains here. Rusty (Sean McDermott), an amiable little steam engine, wouldn't mind winning the great cross-country train race, however. He is up against some formidable competition -- Greaseball, the slick diesel; Electra, an electric-powered blur; Hashamoto, the embodiment of high-speed Japanese technology; not to mention entries from France, Italy, Russia and Germany, all flying the appropriate colors.

The show is the race. More accurately, the show is two trial heats, the race and, since some dirty tricks get sprung on the hero, a rematch. At Rusty's lowest ebb -- elbowed off the track and down in the dumps -- he appeals for help from on high. That leads to the show's biggest effect. In the vee formed by two laser beams aimed at the upper balcony, the cosmos seems to swirl, all glassy green, while in the distance, three great purple tornadoes undulate slowly.

Meanwhile, the music swells and the resonant offstage voice of Jimmy Lockett, singing "I Am the Starlight," urges Rusty to believe in himself. Talk about an encouraging pat on the back. Like a medieval knight going into battle, our reinvigorated steam engine takes to the tracks again and beats the big guys over the L.A. finish line. You could say that "Starlight Express" is "The Little Engine That Could," played out on the scale of "The Ten Commandments."

From the start, the show's novelty has been its roller-skating cast, speeding over the straightaways and leaning into the hairpin turns like seasoned bruisers in the roller derby. With each successive incarnation, however, the track has shrunk. In the still-running London production, the performers leave the stage and circle around the audience. The 1987 Broadway production stayed pretty much behind the proscenium, but the racecourse was three-tiered, which necessitated all sorts of ramps and drawbridges.

The version at the Opera House, although complex by touring standards, is the simplest yet. Once the skaters have taken a spin around the runway, they disappear into the wings and the race continues on film, projected on a large upstage screen. The performers don't reappear in the flesh until the final stretch. This robs the show of a lot of its excitement. Since it is all but impossible to tell who's ahead at any given point, Rusty's gallant last-minute rally from behind has to be taken on faith. If the Kentucky Derby were handled this way, the stands wouldn't exactly be packed.

Lloyd Webber's score comes in a variety of modes -- rock, country-western, gospel, rap. It's mostly pleasing music that avoids the sense of momentousness that is the composer's pitfall. Over-amplification all but annihilates Richard Stilgoe's lyrics, but when you can catch them, they tend to be along the simple-minded lines of "Freight is great" or "Locomotion is what we need, if we're ever going to get up speed."

The show tries to carve out distinct personalities for the various trains and cars. The Red Caboose (Todd Lester), for instance, is a sweet-faced traitor; Greaseball, the diesel (Ron DeVito), is a swaggering Elvis figure; Dinah (Dawn Marie Church), the dining car, is his girlfriend, who laments that she's been "U.N.C.O.U.P.L.E.D." after he throws her over. But Napier's imaginative costumes really do most of the work. Lloyd Webber and his team were far more successful at anthropomorphizing cats. Or maybe it's just harder to love a boxcar.

Nonetheless, McDermott's pluck serves him well as Rusty, and he has the boyishness that sets young girls squealing. As Pearl, an observation car torn between two engines, Reva Rice gets the show's ballads and brings considerable heart to them. Lockett makes a good-natured old steam engine, and if Eric Clausell has modeled Electra, the haughty electric train, after Grace Jones, his performance must be deemed successful.

Director and choreographer Arlene Phillips doesn't ask the impossible of the cast, but every now and then, someone on skates will do a flip or a split or a high kick and you'll gasp. Of course, you wouldn't bat an eyelash if a dancer in tennis shoes kicked the very same kick. Eight little wheels make all the difference.

In more ways than one, "Starlight Express" couldn't run without them.

Starlight Express, music by Andrew Lloyd Webber; lyrics, Richard Stilgoe. Directed and choreographed by Arlene Phillips. Costumes, John Napier; lighting, Rick Belzer and Ted Mather; associate scenic designer, Raymond Huessy. With Ron DeVito, Sean McDermott, Reva Rice, Dawn Marie Church, Todd Lester, Jimmy Lockett, Eric Clausell, Anthony Marciona, Nicole Picard. At the Kennedy Center Opera House through July 14.