It’s been said that if you build it, they will come.

But what if they’ve already arrived — and then you don’t build it after all?

That’s the situation facing suburbs along the proposed Southwest Light Rail Transit line as legislators continue their long battle over the line’s state funding.

The line has been touted by its backers as a spur to future development in the west-metro suburbs. In reality, development has already occurred — quite a bit of it.

For at least a decade, and in some cases longer, city officials and planners have guided development with the Southwest line in mind.

Thousands of apartment units have been built or are underway along the line’s route, with more in planning. Hundreds of millions of dollars have been invested in commercial development, all with the expectation that the trains would be coming.

So what happens if they don’t?

“I think it will be a staggering setback for these communities,” said Peter McLaughlin, a Hennepin County commissioner and one of the Southwest line’s most vigorous supporters. “The essential element, their connectivity to the 21st-century economy, will be destroyed.”

Officials in cities along the proposed line aren’t quite so dire in their predictions. But they agree that failure to build the line would be a major disappointment and alter the pace and tone of future development.

“I think St. Louis Park obviously has done quite well even without having light rail and will continue to do well without it,” said Kevin Locke, the city’s community development director. “But I think if you take away SWLRT, that is a huge loss for the whole region and certainly for St. Louis Park as well.

“Things that could be happening here in the short term with the light rail coming either go slower or just don’t happen at all.”

‘Trying to stay positive’

In Minnetonka and Eden Prairie, home to several of the region’s largest office parks, officials have worked closely with property owners to plan for the rail line’s arrival. The prospect of the line has spurred investments by existing owners and brought new developers into the Twin Cities market, said Julie Wischnack, Minnetonka’s community development director.

“Definitely, people are interested in … a site near light rail,” she said. In recent years, UnitedHealthcare has invested more than $100 million expanding its corporate campus, and light rail was part of the picture, Wischnack said.

“They made some pretty strategic choices in where they located and where they expanded,” she said.

In Eden Prairie, the new owners of SuperValu’s former corporate headquarters were aware of its proximity to light rail, said David Lindahl, the city’s economic development manager. “They saw the plans for a light-rail station right near their front door,” he said.

In Hopkins, construction recently started on the Moline, an upscale, 241-unit apartment building located between the rail line and the city’s downtown. Development associated with the rail line is helping Hopkins meet other planning goals, such as a vibrant and livable downtown, said Kersten Elverum, the city’s director of economic development and planning.

“From a planning perspective, most of the work on transit-oriented development is still relevant, even without the line,” she said. “When I’m really honest about it, I say that Hopkins will be fine.

“But I think the loss that’s most significant [if the line isn’t built] is to our region. I kind of think that is not recognized by the other cities and counties that haven’t been exposed to the research.”

Elverum said Fortune 500 firms want to draw young professionals and that transit is a top reason why they may be attracted to a company. “The weather doesn’t help us, and if we don’t have transit, it will have a huge impact,” she said.

Planners are holding out hope that state officials will hammer out a deal. But they’ve all had their doubts.

“You have no idea of the hours and the efforts we have put into this,” Lindahl said. “It would be a colossal waste not to move forward with the project at this point.

“We’re all trying to stay positive. But it’s concerning that the Legislature has not been able to get behind this project.”