"On the Right Track" attempts to backtrack to a tradition of sentimental comedy best left gathering nostalgic cobwebs: the moppet movies of the '30s. The most popular (and frequently mind-boggling) examples of the form were, of course, the films of Shirley Temple. A listless remake of one of her hits, "Little Miss Marker," failed a year ago.

There's a certain amusing irony in the fact that a black juvenile should turn up two generations later in the sort of role Little Shirley made notorious. Gary Coleman, the crackerjack half-pint from the TV series "Diff'rent Strokes," makes his movie debut as (surprise!) an adorable orphan, 10-year-old Lester, whose sense of insecurity has driven him to take refuge in Chicago's Union Station, where he hustles a living shining shoes, sleeps in a storage locker and supposedly thrives. Washingtonians may feel a cruel irony in Lester's avowed contentment with his unorthodox residence: "On the Right Track" suggests that Union Station is such a clean, safe, attractive, sociable environment that any resourceful kid would derive enormous satisfaction from homesteading there.

Although he manfully fends for himself in most respects, little Lester counts on certain kinds of assistance from grown-ups working in and around the station. Bill Russell, a health club attendant named Robert, appears to stake him to shower and laundry facilities. Herb Edelman's Sam, the manager of a pizza parlor, stakes him to meals, which quiz kid Lester earns by answering trivia stumpers. Lisa Eilbacher's Jill, a penny arcade cashier who aspires to a singing career, fusses and frets over him, presumably like the big white sis he never had.

Russell's character, a calm and thoughtful family man, would appear to be the only plausible father figure in Lester's circle of acquaintances. Evidently sworn to ignore the obvious and offend common sense, the screenwriters pretend that Lester finds the loving adoptive parents he needs in Eilbacher and Michael Lembeck, cast as a social worker named Frank who responds to a complaint about the boy and allegedly makes amends for spending most of the movie trying to exploit him.

Once introductions are out of the way, the scenario becomes a laboriously trivial account of how Lester's prophetic gift for picking the ponies transforms him into a celebrity and inflames many of his patrons with greed. The most feckless of the lot, Frank lets a cool million slip through his fingers.

Quite apart from the cavalierly disregarded racial considerations, Frank and Jill ought to disqualify themselves on the grounds of incorrigible immaturity. It might be easier to imagine a couple as unsuitable as Annie Hall and Alvy Singer taking on parental obligations. In fact, Lester would be better suited to looking after Jill and Frank. Coleman himself reinforces this impression. He's always been a remarkably precocious performer, blessed with a sense of timing usually found in seasoned comic character actors. Little Shirley didn't possess a fraction of his natural acting ability and verbal fluency.

A diminutive 13, Coleman is playing a shade under his real age in "On the Right Track," but his emotional age seems considerably older, perhaps a consequence of surviving critical health problems as a toddler -- a successful kidney transplant saved his life at the age of 3. At any rate, Coleman behaves more like a chubby-cheeked old pro than a cherubic little boy.

It would be preferable if writers and directors respected the peculiar gravity Coleman projects instead of straining for cliche d cuteness. For example, Lester asks one of his regular customers, "What are you workin' on?" The halting reply: "Well, uh, artificial insemination; you know what that is?" Grinning broadly, the little rascal snaps, "Sure, sex without any fun!"

In a similar respect, the most chuckleheaded slapstick sequence requires Lembeck to lug Coleman around inside a suitcase, which is stolen by a derelict, who also steals the kid's clothes (extra cute idea, that one), forcing him to trek back to the station in a cardboard carton. There's a funny payoff here -- Coleman's inimitable elaboration of the line "I ain't never ever goin' out there again!" -- but surely it could have been set up by a less excruciating pretext.