"The Washington metropolitan region is one of the most congested areas in the country, and viable transportation alternatives are needed to accommodate a growing population," says US transportation secretary Mr Anthony Foxx. "When completed, the Maryland Purple Line will connect residents in Montgomery and Prince George's Counties with improved access to jobs, education and medical care and, overall, will help improve the quality of life."

The 26km east-west Purple Line will run from Bethesda to New Carrollton serving suburbs inside the Capital Beltway north of Washington DC. The line will connect four branches of the Washington Metro, three commuter rail lines, plus Amtrak's Northeast Corridor, and will have 21 stations. The line will have a mixture of dedicated rights-of-way and street running.

In addition to the Tifia loan, Maryland Transit Administration (MTA) has applied to the Federal Transit Administration (FTA) for a grant of $US 900m from FTA's Capital Investment Grant Program.

Maryland Department of Transportation will own the project and its private partner, Purple Line Transit Partners, will implement the project on a design-build-finance-operate-maintain basis. The Purple Line project was procured as a PPP scheme under a concession agreement that was executed in April and expires approximately 30 years after substantial completion, which is anticipated in March 2022.