United Telecommunications Inc.'s third-quarter net income more than doubled to $54 million from $24.1 million a year ago. Revenue totaled $1.7 billion, up 20%. The Kansas City, Mo., firm attributed the gains in part to continuing strength in its local telephone operations. The firm, which owns a 50% stake in US Sprint, noted that its share of the loss in the unit was cut to $44,000 from $44.7 million a year ago. US Sprint revenue advanced 34% to $916 million.