Memories of a Railroad Station Girlhood : THE CAPE ANN <i> by Faith Sullivan (Crown Publishers: $18.95; 352 pp.) </i>

Although its setting is small-town agrarian Minnesota around 1940, Faith Sullivan’s novel is very much a story for our time. Its heroine is essentially a woman alone, striving for a life that combines basic gratifications and kindliness. The novel’s narrator and the woman’s best helpmeet and companion is a 6-year-old child. Like the two halves of one of those old-fashioned toys that balances precariously on a table’s edge--the kind of toy that relies on natural law for its effect--mother and daughter balance in a world of social dangers, saved by a link of optimism and mutual trust. “The Cape Ann” is a story for our time because this is the condition of very many of our families.

Lark Ann Erhardt and her mother Arlene live with her father Willie in a storeroom of the Harvester railroad station, where “Papa” is depot clerk. “Mama,” “a head-long person with instincts as sharp as darts” and mistress of all the housewifely arts, has transformed the rent-free room into a serviceable apartment so the Erhardts can save to build a house of their own--the Cape Ann-style house that she and Lark have picked out of a lumber company’s catalogue as the future scene of their domestic happiness. Meantime, Mama scours the depressed economic terrain, with its failed farms and epic unemployment, for some way to make extra money. Lark sleeps in an outgrown crib at the foot of her parents’ bed, helps dump buckets of slop (the room has no proper sink or toilet), goes to school and prepares for her first communion in the Roman Catholic faith.

What unfolds, in Lark’s telling, is principally the story of two years of a child’s growing up--a sequence of adventures, affections, fantasies and close calls remembered with childlike credulity and sensitivity. What emerges in the course of the telling, and gives the growing-up much of its direction, is Mama’s moral independence, her insistence on its practical expression and, ultimately, release from her murderous marriage.

Lark memorizes the “Monkey Ward catalog,” the Elysian scene painted on the face of the clock, the relics found in a hobo camp, the movie star images of William Powell and Myrna Loy, and her “Baltimore Catechism” book, absorbing mysterious significance. She risks making new friends, stealing peeks at forbidden items in the drugstore, selling tickets to the Knights of Columbus picnics, and learning to swim, and reaps thrilling rewards. And she grapples with the meaning of adult behavior and of God, for though Mama is a powerhouse of love and fellow-feeling, some others--including Papa and the threatening deity he invokes--seem divisive and mean.

Mama had converted to Catholicism at marriage and with typical zeal for the thing well done, she drills Lark for her catechism classes with the savage nuns and sews an angelic white dress for her communion. But the only powers for good and harm Mama truly recognizes are human ones. Lark asks if she believes in miracles, and she answers, “Oh yes, that’s how God holds our attention,” and adds, “it’s just the kind of cheap trick I’d pull if I were God.” Cheap tricks, whether Willie’s or those of life in general, are not to be endured but to be protested and in one way or another corrected.

In drinking, bullying and periodic gambling sprees that eat up the precious savings, Willie finds not joy so much as a kind of miserable self-consolation for his wife’s and daughter’s talents for life. He wants “girls and ladies to be pretty, obedient and holy” but sneers at the stylish Arlene who “walks down the street like a duchess” and tells the God-dreading Lark, “It makes me sad when you’re sullen . . . because I know God hates sullen people.” As their independence grows, fed by his irresponsibility as well as their shared successes, Willie’s need to dominate becomes more desperate and violent. Mama plans their escape.

The novel falters at the start, bogged down with the problem of creating a 6-year-old’s narrative voice that is convincingly simple and yet speaks of complex events. But when the author’s gifts for deft characterization and authentic dialogue finally come into full play, “The Cape Ann” develops some of the mesmerizing power of that other, larger-scale novel of marriage and family balances, Christina Stead’s classic, “The Man Who Loved Children.” It develops, as well, into an unforgettable portrait of some of our enduring social frailties.

On the eve of the planned escape, which may yet fail, Mama and her sister, Aunt Betty, visit the Blue Lake Beautee Shoppe for hair-dos suited to a new life in movieland California. “The pinkish gold around her face was pulled back in two rolls that framed the upper face, the rest of the lovely pale red hair fell free, billowing out in fluff at her shoulders,” Lark observes. “She looked like Carole Landis in ‘I Wake Up Screaming.’ ”