In an era when economics threaten to make big bands the dinosaur of jazz, the Jazzmobile/Frank Foster Dream Band, is an encouraging achievement. Last night, the third night of the six-day Wolf Trap Jazz Festival, this 23-piece band featured not the young kids who populate most big bands, but veteran bandleaders like Jimmy Heath, Slide Hampton, Curtis Fuller, Billy Taylor and many more.

Band director Foster began the set with "Shiny Stockings"--a hit from his tenure with the Count Basie Band in the '50s--to illustrate the orchestra's cohesion and discipline.

The show's centerpiece was Foster's seven-movement "Lake Placid Suite," specially commissioned for this band for the 1980 Winter Olympics. The early movements attempted a quasi-classical grandiosity that came off no better than TV theme music. The middle movements, though, were hard bop numbers that yielded exciting solos. Trombonist Fuller engaged baritone saxophonist Kenny Rogers in a good-humored duet duel. Ted Dunbar's restless guitar riffing goaded trombonist Janice Robinson and saxophonist Heath into quicker, fresher solos. Wess' flute solo was delicate without ever getting mushy.

In the opening set, Houston Person elevated the inner-city lounge music of the jazz organ trio to a concert setting. His tenor saxophone's creamy sound mimicked John Logan's organ swells. The trio was supplemented by percussionist Ralph Dorsey and vocalist Etta Jones.