Italy's largest private company Fiat SpA on Tuesday announced a telecommunications alliance and the sale of its railway equipment unit, following through on a strategy to adjust its vast portfolio, which remains heavily weighted toward automobiles. In the telecom deal, Fiat will invest $383 million over three years through its subsidiary Telexis to partner with the Acea-Telefonica group in creating Atlanet, a fixed-line, data network and Internet service. Fiat will have a 28 percent interest in the venture and said the partnership might eventually pursue mobile phone services.