Metro's Purple Line is moving to its next stop.
Maryland Gov. Martin O'Malley announced Friday that the Federal Transit Administration has approved the project to move into the preliminary engineering phase.
That authorizes more detailed plans, schedules, cost estimates and completion of environmental studies.
It will have 21 stations and connect to four branches of the Metro system.
"The Purple Line will be an environmentally-friendly option that will reduce gridlock and connect citizens to economic opportunities throughout the region," O'Malley said.
“The Purple Line is a great way to make the wonderful and diverse communities of Prince George’s County more accessible to residents and visitors and it will help to create new jobs and commerce for our residents,” said Prince George's County Executive Rushern Baker III.
“Governor O'Malley and I have made public transportation one of our top priorities because we understand that Maryland cannot continue to move forward if we are buried in gridlock," Montgomery County Executive Isiah Leggett said.
Officials are hoping to begin construction on the project in 2015 with service beginning in 2020.