Firm buys stake in Federal Signal

OAK BROOK -- Ramius Capital Group LLC said it has taken a 7.4 percent stake in Federal Signal Corp., the maker of fire trucks, and considers the shares undervalued. Ramius holds 3.55 million shares, the New York-based investment company said in a U.S. Securities and Exchange Commission filing Friday. A 7.4 percent stake would make Ramius the second-biggest shareholder in Oak Brook-based Federal Signal, behind Franklin Resources Inc.'s 9.4 percent, according to Bloomberg data.