Jockey Jack Kaenel thought he had left race tracks like Commodore Downs behind him.

He had established himself as a big-league rider, leading the jockey standings at Pimlico this spring, until racing officials discovered that he was two months shy of his 16th birthday and his license was suspended by the state racing commission. Kaenel resumed the sort of life he had lived for almost as long as he can remember.

He and his father hitched a horse van to their camper and drove to Commodore Downs, choosing this rock-bottom race track because it was one of the few places where the elder Kaenel could run his one-horse stable, a rock-bottom 5-year-old maiden. They currently reside in Commodore's dust bowl of a stable area, where there isn't much for Jack to do except observe the passage of time.

How many places like this had they seen? Dale Kaenel had been training horses since he was a teen-ager, living a gypsy life, moving wherever his horses seemed best suited.

"It's hard for most people to understand this kind of life," he said. "Jack was in the fifth grade before he ever got a report card; we never stayed in one place long enough. On the road, if we ran out of money, we'd do whatever we could. I could fix horses' teeth or shoe them. Jack could gallop horses."

He started galloping them when he still was a tot. Lonnie Gray, a trainer at Commodore, remembered, "I was out in Nebraska one year and saw this 8-year-old kid riding two horses Roman style: one leg on each. They called him Cowboy Jack." Young Kaenel rode his first competitive race when he was 10. And soon he started riding at "bush tracks" in places like Anthony, Kan., and Woodward, Colo., where he acquired the education that would prepare him so well for the major leagues of racing.

"The races are part of fairs," he said, "and the purses might be from $50 to $250. The horses don't have to have any papers. The riders are either young ones who are getting ready or old ones who are too heavy. They'll all try to run you off the track." ("When you're a stranger at those places," Dale Kaenel interjected, "they'll try to eat you alive.")

"I won more than 400 races," Jack said. "I won the 100th running of the Watermelon Derby at Rocky Ford, Colo. When you won they gave you a great big watermelon with a ribbon around it. I raced in mule races, too, at the fairs I rode at. I won the Deer Trail Mule Derby."

Members of the bush-racing fraternity thought that the young rider had special gifts; his father thought so, too. So he moved his two-horse stable to a small licensed track in Canada where Jack misrepresented his age and started riding, and then virtually gave up training to accompany the boy to bigger tracks.

To outsiders, Dale Kaenel might seem like the pushiest kind of stagedoor father. He's not; he's a realist. When a family is eking out survival with a couple cheap horses and whatever skills they have to sell, they do whatever they can. And they don't worry about niceties like the rules requiring jockeys to be 16 years old.

The people at Commodore Downs understand this. "The Kaenels are heroes here," said Lonie Gray. And after his suspension for being "underage," Jack is viewed more as a martyr than a cheater by race trackers who expect even 10-year-olds to pitch in and contribute to a family's economic well-being.

Jack underwent an appendicitis operation shortly after the Maryland Racing Commission suspended his license. He is taking it easy, lying around the camper listening to his father strum his banjo. In the next week or two, the Kaenels may point their camper in the direction of Woodward, Okla., and go to the bush track there so Jack can do some riding and get fit again.

On July 27, his 16th birthday, he plans to ride at Timonium. The next day the Kaenels will set out for Saratoga, where Jack hopes to establish himself in the very biggest of the big leagues, finally leaving the places like Woodward and Rocky Ford and Commodore Downs as only vague, distant memories.