Des Moines lawmakers have endorsed a potential ballot measure that would extend light rail from Sea-Tac International Airport to Tacoma.

This branch of the proposed expansion includes seven stations between the airport and the Tacoma Dome. One of those potential stations is to be located between Kent-Des Moines Road and South 240th Street in Des Moines.

Lawmakers said they would support a ballot resolution only if it calls for connecting Seattle to Tacoma as promised.

The Sound Transit Board expects to make final decisions this summer about the plan and when to present it to voters. Since a combined roads and transit proposition failed on last year's ballot, the board will present another plan either in November or in 2010.

"They're looking at options for a new bond measure or levy measure," Mayor Pro-tem Dan Sherman said. "Two of these options would stop well short of connecting Seattle and Tacoma as proposed in Proposition 1 in November 2007."

Sound Transit is seeking public feedback on three plans for South King County that vary in length. One goes from the airport to South 200th Street, the second goes from Sea-Tac to Kent-Des Moines Road and South 240th Street, and the third plan goes from Sea-Tac to Tacoma. Des Moines only supports the third plan.

"Whatever support this has, it has support based on what they said in the build-out. And that was the build-out that we were told," Sherman added.

For more information about mass transit options, visit http://future.soundtransit.org/projects.aspx.

Council members also passed an amendment to a development agreement with the Port of Seattle for the Des Moines Creek Business Park.

The amendment calls for the port to provide compensation for specific development within the business park. The port is scheduled to consider the amendment next month.

Public Works Director Grant Fredericks briefed the council on the document, which reflects continued negotiations with the port and city staff.

"We're not exactly sure what this project will look like, because we haven't yet been provided a master plan," Fredericks said. "Anything not covered here will be picked up in the second development agreement."

In other business, a public hearing on the Cedar Heights preliminary development agreement was continued until June 26. The housing development borders on South 232nd Street and 14th Avenue South.