All the pieces are coming together to return St. Paul's Union Depot to its original purpose: a train station.

The planned $237.5 million renovation project includes getting the depot ready for both the Central Corridor light rail transit project, which is scheduled to open in 2014, as well as high-speed rail to Chicago, says Finance & Commerce.

The timing on that Chicago line, though, is way, way up in the air, Jim McDonough, the Ramsey County commissioner who’s also head of the Ramsey County Regional Rail Authority, told the publication.

Earliest possible date is 2014, and more likely is 2015 or 2016, or worst-case: 2018. That's if the current political will continues locally and in Washington, and the deal happens at all.

The county rail authority has a design-build contract with Mortenson Construction, which will report the final scope and price for the project in August. If the numbers work and other details are resolved, construction could start in September.