Arbitrary whimsy is a sand trap on the fairway of American indie filmmaking, and you could be forgiven for thinking you'd stumbled off course based on a synopsis of The Station Agent: A dwarf, a hot dog vendor, a mother mourning a dead son, a pregnant teenage librarian, and a chubby schoolgirl share quality time around an abandoned railroad depot in rural New Jersey. That writer-director Tom McCarthy manages to circumvent most of the squirm-making or punchline-pulling bumps on such touristy terrain is a relief. That his strange, often funny film is so well-disciplined and deadpan refreshing is an achievement.
It so happens that the character of Finbar McBride (Peter Dinklage), a railroad enthusiast who inherits the depot from a fellow trainspotter as the story begins, is a dwarf. It so happens that the first guy Fin meets when he moves into his quaintly decrepit new home is Joe (Bobby Cannavale), possibly the most gregarious, open-minded Cuban-American vending-cart operator in all of the Garden State. When Joe asks Fin, ''Do you people have clubs?'' he means, you people who love trains.
Things like that happen to the station agent all the time in ''The Station Agent.'' Some passersby are at their hurtful, name-calling worst (and neither actor nor filmmaker shies from uncomfortable incidents of indignity). But just when Fin is braced for pain, unfettered kindness is offered. Olivia (Patricia Clarkson), who lives in town, almost runs him off the road not because she's unnerved by the sight of such a stranger, but because she's sunk in her own sadness at the wheel of her SUV. A librarian (Michelle Williams) warms to the new book lover at once; a little girl (''Lovely & Amazing'''s Raven Goodwin), as matter-of-factly unparented as she is black in a very white neck of the woods, adopts his train passions as her own.
In the movie's one mood bobble -- it's a dwarf-at-a-bar thing -- Fin indulges in a drunken wallow of anger. But the lovely, underplayed irony of ''The Station Agent'' is that the title fellow is so resigned to a life of self-containment as self-protection that he claims his depot as an exile's sanctuary. And instead, it's Grand Central Station, a rush hour of friendships. Anyhow, Dinklage's Fin is such a charismatic loner, with his dry-ice sense of humor and magnetic aura of hard-earned calm and competence, that it's natural to be attracted to the size of his personality.
In fact, the camera itself is attracted to the handsome actor, often hovering close on his wearily expressive gray eyes. And when Dinklage blends his rich baritone voice in conversational duet with Clarkson's smoky alto, as Fin and Olivia deepen their friendship, the connection between the two isn't arbitrarily whimsical -- it's naturally erotic.