Cost estimates are in on a potential light rail route connecting Issaquah and Totem Lake via Bellevue. The price tag? Up to $3.379 billion.

The Sound Transit board held its first workshop Friday for ST3, the agency’s planned next step in expanding light rail and rapid bus transit in Seattle, Everett, Tacoma and the Eastside following completion of the system spine under ST2 in 2023.

The workshop saw Sound Transit executives brief the board on the projected costs and ridership of a battery of potential projects first introduced in August, “following up and closing the loop on the work [done] earlier this year,” said Ric Ilgenfritz, Sound Transit’s executive director for planning, environment and project development.

The agency based their ridership projections on population and employment information from the Puget Sound Regional Council, planning and project development manager Karen Kitsis said.

Ilgenfritz noted that the proposals and their projections were strictly conceptual, but would help establish the scope of the transit plan as the board hashes out the specifics of ST3 in order to craft a package for voters.

The board must complete work on its system plan by June in order for a package to make it in front of voters in November 2016.

The hypothetical projects would total approximately $30 billion in capital costs if they were approved in full, board member and Issaquah Mayor Fred Butler noted after looking over a tally handwritten by Redmond Mayor John Marchione. The proposed Eastside projects would themselves cost nearly $7.6 billion.

The Issaquah/Totem Lake light rail corridor is the most expensive of the Eastside projects — and the most desired, according to the results of a survey Sound Transit conducted over the summer. The line — which would be split into two segments connected at Wilburton Station in Bellevue — would have eight stops and serve between 12,000 and 15,000 riders per day by 2040.

“This would extend from Totem Lake to Bellevue via the Eastside rail corridor and then continue east along [Interstate 90] to Issaquah,” Kitsis said. “A connection to East Link would be provided … at Wilburton Station.”

Obstacles facing the proposed line included abutments against residential and historical properties, as well as construction interrupting East Link operations.

The proposed Totem Lake-to-Issaquah light rail line would intersect with East Link and potentially halt East Link travel during construction. Image Credit: SoundTransit3.org

Another light rail project would see the East Link line extended to downtown Redmond. The project was estimated to cost more than $1.1 billion with up to 5,000 riders a day in 2040.

Rapid transit bus corridors connecting Kirkland to Bellevue, and Lynnwood to south King County via Interstate 405, were also proposed. The I-405 corridor proposal carried four alternative plans balancing travel time and geographic coverage.

Bellevue Mayor and King County Councilmember-elect Claudia Balducci said she doubted Sound Transit’s projections for the I-405 bus corridor that showed identical ridership for each option, remarking that the models were “not intuitive.”

Additionally proposed but little discussed was a proposed park-and-ride in north Sammamish. The facility would provide 200 commuter parking stalls at a cost of up to $12 million.

Executive Director of Finance Brian McCartan is crafting the financial plan for ST3, which he said would rely on a combination of sales tax, property tax, car tab tax and a bond issuance. He added that he expected the project to be a “very attractive” investment to the federal government.

The amount of a bond issuance would come down to the board’s decisions regarding which projects would make it into the final system plan, the length of time the program would cover, the level of tax imposed on residents and the equity of investment and revenues by county.

Requirements in state law for explaining revenue gains and benefits by county could be particularly challenging for a project that traverses King, Pierce and Snohomish. When the board crafted the 1996 Sound Move and 2008 ST2 packages for voters, it approached the requirement by dividing the territories into five subareas. That approach may not work for the latest transit package, McCartan said.

“You’re looking at connecting, for the first time, all of the region,” McCartan said. “So a rider from one subarea could take a light rail trip to any other subarea. That’s a very different proposition from an equity point of view and I know the board has already started to think about how to define equity within that context … There’s some hard calls there but what I can tell you is that you have the flexibility to make that determination and to a structure a plan you think best builds out the regional system for the benefit of the whole region.”

Friday’s briefing kicked off what Ilgenfritz said he expected to be an “aggressive” seven-month process to develop a concrete proposal in time for the November 2016 ballot. The schedule will see the board accept responses to the proposed scope of ST3 by Jan. 21, draft a system plan by March, kick that plan out to the public in April and adopt a final plan in June.

Some board members questioned how the short time table would affect the public information process.

Mayor Balducci said she wanted to ensure Sound Transit was in communication with other transit agencies in order to determine how King County Metro, Pierce Transit and Community Transit might mesh with the new Sound Transit network.

“It would be nice to really show the public how they’ll get from Point A to Point B,” she said.

Meanwhile, Mayor Butler wondered aloud if there was an opportunity to pursue a plan resembling ST Complete, the alternative “full buildout” transit plan proposed by grassroots organization Seattle Subway.

Butler noted that McCarten’s tax collection timetables showed that a 24-year tax collection plan would provide gains in revenue well beyond the scope of all the projects reviewed. Tackling more projects now could help avoid further lengthy public transit development processes in the future, he said.

“ST3 is an abbreviated long-term process that we’re going through and I would feel a lot more comfortable — and I’m sure a lot more jurisdictions would feel more comfortable — if their project was in ST3 and going to happen in 20 years, so they don’t have to go through an ST4,” he said.