Four teams of private companies have been chosen to compete for a public-private partnership to design, build, operate, maintain and help finance construction of a $2.2 billion light-rail Purple Line in the Maryland suburbs, state officials said Wednesday.

The four were chosen from six teams that submitted “statements of qualifications” in mid-December.

Maryland Department of Transportation officials said they plan to select a bid by early next year. That would allow construction of the 16-mile line between Bethesda and New Carrollton to begin in spring 2015 and open in 2020, officials said. The line connecting Montgomery and Prince George’s counties would have 21 stations, including in Silver Spring, College Park, Langley Park and the Riverdale area.

A public-private partnership on a Purple Line would be the first for a Maryland transit project. Only one other U.S. transit project — in Denver — has such a far-reaching public-private agreement, but it is still under construction.

Maryland officials said they will ask that private companies contribute $500 million to $900 million toward the line’s construction. Under a contract, which would span 35 to 40 years, the state would pay the team annually to operate and maintain the line based on certain performance standards.

The shortlisted teams selected to submit bids are:

Maryland Purple Line Partners: Vinci Concessions, Walsh Investors, InfraRed Capital Partners, Alstom Transport and Keolis.

Maryland Transit Connectors: John Laing, Kiewit Development and Edgemoor Infrastructure.

Purple Line Transit Partners: Meridiam Infrastructure, Fluor Enterprises and Star America Fund.

Purple Plus Alliance: Macquarie Capital and Skanska Infrastructure Development.

Teams were judged on prior experience, personnel, organization, financing capacity and overall approach, officials said.

The Purple Line, which is seeking $900 million in highly competitive federal construction funding, would connect neighborhoods with Metrorail stations and Amtrak and MARC commuter rail stations. The state has allotted $750 million to the project.

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