Maryland just moved another step closer to building a light-rail Purple Line in the Washington suburbs.

As of noon Tuesday — the deadline for submitting “technical” bids — the Maryland Transit Administration (MTA) had received proposals from four teams of private companies outlining how they would design, build, operate and maintain a Purple Line, state officials said.

All cost details — the overall construction cost and how much the state would pay the private team to operate and maintain the line, as well as help finance its construction — will be included in financial proposals due Dec. 8.

All four teams of private companies “short-listed” to bid on a 35-year public-private partnership for the Purple Line project submitted proposals before the deadline, said MTA spokesman Chuck Brown.

The four consortiums of private companies are: Maryland Purple Line Partners, Maryland Transit Connectors, Purple Line Transit Partners and Purple Plus Alliance. Each team consists of up to a dozen or so companies, including some of the world’s largest engineering and construction firms.

The proposals are each several hundred pages long, Brown said. According to state plans, the MTA would own the rail line and set fares, while private companies would design and build it over about five years, and then operate and maintain it over 30 years. The state would pay off the private sector’s debt service costs and pay the private team monthly for operating and maintenance costs. The monthly payments also would include the private sector’s profit and could be reduced if certain performance standards — such as clean trains and reliable service — aren’t met, state officials have said.

State officials said they plan to begin negotiations with a preferred team by Jan. 15 and make the final selection in February. The state’s Board of Public Works, which approves major contracts, will then review it in March, Brown said. Construction is scheduled to begin in 2016, with trains running in 2021.

State officials have said their latest cost estimate for a Purple Line’s construction is about $2.16 billion, but the final cost won’t be known until a bid is selected. The 16-mile line would run between Bethesda in Montgomery County and New Carrollton in Prince George’s County. The line would provide the first direct suburb-to-suburb rail link between the two counties and link Maryland’s ends of the Metrorail system with neighborhoods, MARC commuter stations and Amtrak.

Supporters say the line would attract development to older inner-Beltway suburbs, focus growth and provide faster, more reliable east-west transit than buses. Opponents have said the project is too expensive, would disrupt communities, and cause irreparable harm to the wooded Georgetown Branch Trail along the rail alignment between Bethesda and Silver Spring.