Critics of the authority overseeing the $6 billion Dulles Rail project say the agency is addressing problems its had with nepotism, contracting improprieties and secrecy — even as officials disclosed further evidence of nepotism and the agency refused to publicly disclose key details of internal audits.

“We have worked hard with public and private stakeholders to tackle some of the challenges at [the airports authority],” U.S. Secretary of Transportation Ray LaHood said at a meeting of the Metropolitan Washington Airports Authority Wednesday. “I have confidence in the chairman. I have confidence in the current board. I have confidence in the current staff.”