Transit planners studying different routes for the northern stretch of the Purple Line bus-rapid transit project have found that further tweaking is needed to qualify the project for millions in federal funding.

That's because the White Bear Lake City Council, citing concerns about the effect the Purple Line might have on its downtown, earlier this year barred the line from entering the city — effectively changing the line's route.

The 15-mile line, formerly called the Rush Line, was supposed to link the downtowns of St. Paul and White Bear Lake, running through St. Paul's East Side, Maplewood, Vadnais Heights, Gem Lake and White Bear Township.

The Metropolitan Council switched gears and is now studying three alternatives for the line's northern-most stop: Vadnais Heights, between Hwy. 61 and Interstate 35E near County Road E or Willow Lake Boulevard; the Maplewood Mall Transit Center, Maplewood; or Century College, which straddles White Bear Lake and Mahtomedi.

As planners updated models looking at population forecasts along the route, potential ridership, capital costs and other criteria, they found the line "would not quite meet the threshold for federal funding," said Nick Thompson, Metro Transit's deputy general manager of capital programs.

"We have to make some changes to make it eligible," he said. "We have more work to do."

When the line was going to terminate in White Bear Lake, it was expected to cost $475 million — with the Federal Transit Administration (FTA) paying about $238 million and Ramsey County covering the rest. It's unclear what a new route would cost.

That FTA grant program — called the Capital Investment Grants program — has helped pay for the Blue and Green light-rail lines and five other major transit projects in the Twin Cities. The program, described by the Met Council as "rigorous and competitive," requires a local match.

Federal funders affix a rating to each project across the country during the multi-year planning process. Projects must receive at least a medium rating to be eligible for funding, for which the previous version of the Purple Line had qualified. It's one of 15 transit projects in the national pipeline vying for funds.

One issue with the Purple Line is that population growth among east metro communities hasn't been as robust as the projections made by planners in 2014. In addition, building costs are likely higher.

Thompson said he's confident that planners can achieve at least a medium rating with the new routes being considered. The situation is "not uncommon," he said, noting that other transit projects in the Twin Cities have made similar changes.

A year ago, the Gold Line bus-rapid transit project needed to add a $58 million park-and-ride facility and Washington County service center at the Interstate 494 Station in Woodbury to beef up its FTA rating. The line is slated to connect downtown St. Paul with Woodbury.

The new Purple Line wrinkle "is a huge development," said Tim David, a White Bear Lake resident who leads a coalition opposing the line.

"It shows that communities can regain the ability to design their communities rather than having these mega-projects pushed onto them by a behemoth agency with no accountability to residents and businesses, and little transparency," David said, referring to the Met Council.

"The fact that the project does not meet FTA criteria if it goes to Maplewood Mall indicates this mega-project is not a good fit and not a good use of public dollars," he added.

But Ramsey County Commissioner Victoria Reinhardt, a White Bear Lake resident who has long championed the Purple Line, said she's confident the project will make the needed adjustments to qualify for federal funding.

When asked if Ramsey County would pick up the tab if federal funding was not forthcoming, Reinhardt said: "I have no idea. We haven't discussed it."