Dozens of steel pilings driven into the ground 32 years ago near Falls Church that could carry future Metro trains over Interstate 66 to Dulles International Airport are at the center of a safety investigation.
Federal officials are looking at whether enough testing has been done to ensure those footings wouldn't crumble under the weight of a bridge carrying trains.
Documents obtained by The Washington Post show the contractor building the first leg of Metro's extension resisted testing most of the foundations until federal officials intervened.
Federal Transit Administration head Peter Rogoff says his agency has genuine concerns about the engineering plan. The agency has said construction of the bridge can't proceed unless the FTA certifies the design's safety.