The U.S. Justice Department says it's sued KBR Inc, accusing the company and a Kuwaiti subcontractor of improperly charging the federal government for the costs of delivering and installing trailers for troops in Iraq. The lawsuit came days after the Justice Department dropped a similar but unrelated case over KBR's costs for private armed security in Iraq. The latest lawsuit alleged that KBR-hired subcontractor First Kuwaiti Trading Company inflated its crane, truck and driver costs and misrepresented delays on the installation of more than 2,250 trailers.