Sound Transit has beefed up the list of Snohomish County projects it may pursue in its next phase of expansion.

Delivering light-rail service to Everett continues to be agency leaders’ top priority for Snohomish County in the $15 billion expansion known as Sound Transit 3, or ST3 for short.

Last week the agency Board of Directors made several additions to the roster of potential projects in the county including building a 1,000-stall parking facility at Everett Station and new parking structures at future Link rail stations in Lynnwood and Mountlake Terrace.

Also tacked on for consideration is a study on extending light rail service along State Highway 522 and providing bus rapid transit service between a future rail station on I-5 and the UW Bothell campus.

Not every one of these items is assured of making it into the final ST3 plan expected to be on the ballot in November 2016. Voters at that time will be asked to approve the plan and the increases in sales tax, property tax and car-tab fees needed to pay for it.

In the next few months each project on the ‘candidate’ list will be evaluated on such criteria as cost to build and maintain, projected ridership that might be generated and other benefits and risks it poses.

The agency board could begin as early as December to whittle down the list and may take until next summer to settle on what will wind up in the ballot measure.

“It’s not like any decisions have been made,” said Paul Roberts, an Everett city councilman and vice chairman of the Sound Transit board. “They’ve all been put into the bag of things to look at for ST3.”

Leaders in Everett and Snohomish County, including Roberts, have made a strong push for a light-rail route that would serve Paine Field and Everett Station, then continue north to the area around Everett Community College and Providence Regional Medical Center Everett.

The board also wants analysis done of two other routes between Lynnwood and Everett Station. One would follow I-5 and the other would travel along I-5, Highway 99 and Evergreen Way. Only one route will be specified in the ballot measure, Roberts said.

“I want to make sure that we get to Everett. If we don’t get to Everett it will be tough to get ST3 passed,” Roberts said.

The light rail additions aren’t likely to get built until the 2030s, if the schedule holds.

Sound Transit is on track to begin constructing light rail service to Lynnwood in 2018 and be completed in 2023 under the last voter-approved expansion. The new segment would include stops at the Mountlake Terrace Transit Center, Northeast 185th Street in Shoreline and 145th Street in Seattle. It’s predicted to carry 63,000 to 74,000 riders each weekday by 2035, with a Lynnwood-to-Seattle trip taking an average of 28 minutes.

Potential ST3 projects include adding parking at the station on 236th Street in Mountlake Terrace and constructing crossings on I-5 for buses and vanpools to reach rail stations at 164th Street SW and 128th Street SW — should those stations be built.

Service on the Highway 522 corridor is a significant addition to the ST3 list.

The board wants to consider bus rapid transit on 145th Street between the station at I-5 and Highway 522, continuing on to UW Bothell.

During the Aug. 21 meeting, the board also padded the list of potential projects in King and Pierce counties.

They did so without any controversy. Their mood may change when it comes time to settle on the final components of the ballot measure.

“There is a big demand for service,” Roberts said. “It is time for us to look at the Puget Sound region as a region. That means Everett to Tacoma to Redmond and everywhere in between.”

Jerry Cornfield: 360-352-8623; jcornfield@heraldnet.com.