BAGTIME -- Gateway Theater, 4th and E Streets SW. Reservation, 554-5134.

Tried-and-true show tunes and fancy footwork do not always add up to a show, at least when there's no discernible script to hold it all together. As of Wednesday's preview, the single bright spot in "Bagtime" was its talented young cast.

"Bagtime" gets off to a shaky start with a Big Apple sequence in which a Sailor, a Hooker, a Businessman, a Bag Lady and a few other cliches strut around to ersatz Gershwin music to symbolize the City as Humanity. But at least these characters have some connection to each other.

For the rest of the show, the performers stream across the stage signing bits and pieces of Broadway tunes and Top 40 hits in odd costumes that seem to have nothing to do with the song they're singing, the song they have just sung or the song they will sing next. The voices are good and there's orginal music lurking there somewhere, according to the program, but it's hidden under a barrage of oldies whizzing by like a tape recorder on fast forward.

The whole affair is supposed to be the Bag Lady's fantasy. First the fantasy setting is supposed to be outer space, then the country, then underwater. Only what do those three women in gauzy blue dresses singing "If Mama Was Married" from "Gypsy" have to do with an underwater fantasy? Or how does a woman in a dog suit intoning "A Hard Day's Night" to three Canadian Mounties relate to the country? And where is the Bag Lady? The scenery doesn't clarify matters any. A few lackluster slides are occasionally projected onto eight rear screens when what's needed is some real dazzle.

The Bag Lady does reappear in the finale. Surrounded by the rest of the cast in white tuxes, she beatifically sings "This is where I belong." Where? Is she back in New York? Is she dead and in Broadway heaven? Maybe she should look in her bag. She just might find a script that will tell us all what's going on.