The makeover will double the concourse passenger capacity by adding an additional 20,000 square feet, new restrooms, boarding gates and seating areas and remake the current Club Acela Lounge as a modernized Metropolitan Lounge.
The concourse, which dates back to the 1980s, serves both Amtrak routes as well as Virginia Railway Express and Maryland Area Regional Commuter Rail passengers.
The project was first announced in 2016.
The renovations are a partnership between the Union Station Redevelopment Corporation, the Federal Railroad Administration and real estate developer Akridge, though funding for the project will come predominantly from Amtrak.
When they go into service by the end of 2022, the trains will carry up to 386 passengers, a 30 percent increase, and will operate initially at speeds up to 160 miles per hour, and be capable of speeds up to 186 miles per hour.