Supporters of building a Metrorail line to Washington Dulles International Airport through a tunnel under Tysons Corner have withdrawn a lawsuit against the U.S. Department of Transportation that sought to block the approved project if their proposal wasn’t reconsidered, the group’s president said Tuesday.

Tysonstunnel.org’s suit said the Federal Transit Administration couldn’t approve funding for the 23-mile line’s first phase to Reston because the construction contract wasn’t bid competitively and the underground route wasn’t adequately weighed as an alternative to the proposed aerial track in Tysons.