The Southwest Light Rail Transit project’s charge toward $2 billion has local policymakers twirling their budget lassos.

When it meets again May 20, the Met Council is expected to review a list of ideas for reining-in project costs. The sticker shock was widespread when the agency’s latest analysis of the light-rail project, released in April, revealed the price tag had grown $341 million from the previous estimate of $1.65 billion, a 20-percent increase.

The 16-mile extension of the Green Line from downtown’s Target Field station to Eden Prairie will now open in 2020 at the earliest. Project director Mark Fuhrmann expected a mix of large and small cuts would be used to eliminate “much if not all” of the latest increase.

“Any of those options that would be $100 million or greater … would have to require some shortening of the light rail line,” Fuhrmann said.

Any cost-saving proposals must be weighed against the impact on the line’s future ridership as well as its standing with the Federal Transit Administration, said Fuhrmann. Southwest light rail is competing against six other transit projects in the New Starts program run by the FTA, which is expected to eventually contribute half of the funding for the line.

Furhmann said the risk that costs will continue to rise is decreasing.

“At 40-percent design development, much of the design risk has been now squeezed out of the project as we know where everything is: where all the stations are going to be, where exactly the track is, where the bridge foundation and piers are going to need to be,” he said.

The factors driving the shocking April analysis included additional engineering and environmental studies. Engineers also discovered poor soil conditions throughout the 16-mile light rail corridor and soil contamination in St. Louis Park and Hopkins.

Both Gov. Mark Dayton and Adam Duininck, Dayton’s newly appointed Met Council chair, acknowledged that escalating costs put the future of the Green Line extension in question. Met Council has spent about $59 million on the project to date.

In addition to identifying options for trimming the budget, Dayton directed the Southwest project office to go back and review the alternatives to building a light rail line and to have a third party review its estimates of construction costs. He also ordered a separate third-party review of Met Council’s ability to handle what has grown into the largest transit project in state history.

At the May 6 meeting of the project’s Corridor Management Committee, a group of local elected officials and agency representatives, Edina Mayor Jim Hovland said he opposed rerouting the line or scrapping the project in favor of buses.

“I think it’s really important to keep in mind we’re trying to build a (light-rail) system here,” Hovland said. “… I think this is the route we should stick with.”