The Metropolitan Council, Hennepin County and other Twin Cities area counties have agreed to prop up the financing for the Southwest Corridor light rail project, filling in a $144.5 million funding gap.

The gap was left after the Legislature declined to approve $135 million in proposed state funding in a dispute that lingered as lawmakers and Gov. Mark Dayton wrangled over a potential special legislative session this summer.

Hennepin County committed an extra $20.5 million to the project, raising its contribution to $185 million. The county board approved the extra funding on Tuesday.

Hennepin and other Twin Cities counties matched that $20.5 million in a meeting Wednesday, approving the funding by a 7-4 vote. The Met Council pledged $103.5 million in "certificates of participation" and backed the plan Wednesday afternoon.

The $1.86 billion line would run 14.5 miles from downtown Minneapolis to Eden Prairie, stopping at 15 stations. The project's environmental impact statement has already been finished, and orders for light rail cars could be placed as soon as this fall. Planners hope to open in 2021.

Met Council Chair Adam Duininck said he intends to work with the Legislature to secure Southwest light rail funding next year so that the council won't ultimately have to fill the gap.

The counties chipped in through the Counties Transit Improvement Board, a regional joint powers board that allocates proceeds from a quarter of a percent Twin Cities area transit tax and motor vehicle fees.

The eight-year-old board has already put nearly $400 million into the Green Line connecting Minneapolis and St. Paul, as well as preparations for the Southwest and Bottineau lines.

Chair Peter McLaughlin, a Hennepin County board member, said the stopgap measure was the only way to "thread the needle" and keep Southwest light rail. He said the costs of delay could add tens of millions of dollars to the project cost and kill the line.

The CTIB board members, county commissioners from all around the Twin Cities, split on the plan. They worried about the last-minute nature of the solution and the potential impact of a lawsuit against the line.

Commissioners from the east side of the Twin Cities region said they worried the new funding represented a tilt toward the west metro and that their constituents wouldn't get their sales taxes back in transit investments they could use.

Dakota County Commissioner Nancy Schouweiler said she wanted to hear more about where the money is coming from for an additional contribution to Southwest.

"What does it do to the projects next in line such as Gateway and Riverview?" she asked. Her board already voted earlier this summer to pull out of CTIB in 2019.

Dakota County Commissioner Tom Egan cited a CTIB vote earlier this summer to require his county to chip in an additional $7.5 million for the proposed $150 million Orange Line rapid transit bus route running from Minneapolis to Burnsville.

"When do we say enough is enough?" asked Anoka County Commissioner Scott Schulte. He said the additional contribution also risked signaling to the Legislature that transit doesn't need state participation to move forward.

But Washington County Commissioner Lisa Weik said she worried that turning down the last-minute funding risked shutting down the Southwest line altogether.

"It risks having the Federal Transit Administration losing confidence in our region and our ability to fund transit projects," she said, adding that could scuttle the proposed Gateway line from St. Paul to Washington County, as well.

"This is not a good option," said Duininck, the Met Council chair. But he said further delay could add to costs and price the project out of reach. "We gave the governor and Legislature as much time as we possibly could."

Editor's note (Aug. 31, 2016): An earlier version of this story described Duininck as expecting the Legislature to fully fund Southwest light rail next year. To clarify, Duininck said he intended to work with the Legislature to secure state financing.