The Ramsey County Regional Rail Authority on Tuesday picked Mortenson Construction to lead the $150 million renovation of the historic Union Depot in downtown St. Paul.

Commissioners voted unanimously to authorize Rail Authority staff to negotiate a contract with the company.

Staff members hope to bring back a deal -- as well as a project budget, financing plan and schedule -- for commissioners to approve on Jan. 12, said Jolly Mangine, the county's director of property management.

The county's long-stated goal has been to restore the languishing depot into a regional transportation hub for trains, buses, bikes and taxis.

"The Union Depot is our diamond in the rough and is critically important to transportation in the region," said Commissioner Rafael Ortega.

The block-long building faces 4th Street and sits between Wacouta and Sibley Streets. County officials estimate the project will bring up to 1,350 jobs during design and construction. Construction is expected to be completed in 2012.

Also Tuesday, Rail Authority commissioners approved giving the Metropolitan Council up to $82,000 for a study of how three additional stations along University Avenue would affect the areas when the Central Corridor light-rail line is built.

The study was requested by the Federal Transit Authority, which is being asked to provide half of the funding for the $941 million project. The study would need to be done if the three stations --at Hamline, Victoria and Western Avenues -- were to be built during initial construction.

Those stations are a top priority for the county and the city of St. Paul. Basic foundations have already been included in project documents, but officials and community members have pushed for complete build outs.

There will be a 30-day comment period on the results of the study, as well as a public hearing at the end of January.

The 11-mile Central Corridor will connect the downtowns of St. Paul and Minneapolis and is expected to begin running in 2014.

Chris Havens • 612-673-4148