A proposed deal to fund the Real Salt Lake soccer stadium in Sandy has complicated plans to pay for commuter rail through Salt Lake County, according to House Speaker Greg Curtis.

Instead of using hotel-room tax dollars to fund the line, county leaders may have to forgo building one of four new TRAX lines in favor of building commuter rail, said Curtis, a Sandy Republican.

"The Utah Transit Authority has assured me that you can get at least three (TRAX) lines and commuter rail with a quarter-cent sales tax," he said. "I'm not advocating for any three over the other, but with Utah County voting this fall on commuter rail, I think that (commuter rail) should be in the mix."

Utah lawmakers are currently debating whether a special session should be held this September to authorize a quarter-cent sales-tax hike for mass-transit expansion in Salt Lake County.

The sales-tax hike would be in lieu of a property-tax increase to build four TRAX extensions.

Salt Lake County officials approved the property-tax increase for the ballot last month, but it was done with the understanding that lawmakers would be lobbied to give authorization for a sales-tax hike instead.

Complicating the decision to switch to a sales tax — and what projects to use it on — is a vote by Utah County commissioners earlier this month to put a quarter-cent sales-tax increase for commuter rail in their county on the ballot.

Senate President John Valentine, R-Orem, said Monday that it didn't make sense to put a tax increase for commuter rail on Utah County's ballot unless funding was found for commuter rail in Salt Lake County. Without the line in Salt Lake County, commuter rail in Utah County would just dead-end at the Point of the Mountain. And residents wouldn't be able to travel by rail into Salt Lake City or beyond, which is the purpose of a regional rail system, he said.

"If we can't get some solution for commuter rail that includes a link between Provo and downtown Salt Lake, it'll fail and there's no use even having a vote in Utah County, " he said. "You don't want to build a bridge to nowhere."

But Chad Eccles, transit planner with the Mountainland Association of Governments, said that if Utah County voters approved a sales-tax hike without funding for commuter rail in Salt Lake County, the money could be used for highway projects. The association does long-range transportation planning for Utah County.

"There's definitely some flexibility, but we intend to move forward as fast as we can on commuter rail, because it's crucial for the I-15 mitigation," he said.

Meanwhile, mayors in the cities that would get one of the four TRAX lines said Monday that it wouldn't be fair to drop a TRAX line in favor of commuter rail. The four lines are proposed to run to West Valley City, Draper, the Salt Lake City International Airport and South Jordan.