The final list of ST3 projects, which were selected following extensive public consultation, will add 60km and 37 stations to the network. The revised list of projects will be the basis for the final ST3 document, which the board will consider on June 23.

Under the revised timeline, the extensions to Federal Way and Redmond will open in 2024, four years earlier than previously proposed. The lines to Ballard will open three years early in 2030 and the Ballard extension will be brought forward from 2038 to 2035. The extension to Everett via Paine Field will open in 2036 instead of 2041 and the Tacoma Link - Tacoma Community College line will be brought forward by two years to 2039.

Sound Transit says it will work with partners to further improve delivery timescales for these projects wherever feasible.

The draft plan now also includes an extension of the Issaquah - Bellevue line north to South Kirkland; a new station at Northeast 130th Street in Seattle, which moves from provisional to fully-funded status; and increased investment in Sounder commuter rail to boost capacity and extend the line to Tillicum and DuPont.

The improved timelines and additional projects are primarily enabled by refinements including adjusting the financing plan for the ST3 measure to modestly increase the issuance of bonds, improving the region's financial capacity by approximately 8% or $US 4bn.

The overall $US 54bn cost of ST3 would be funded in part through new voter-approved sales, motor vehicle excise, and property taxes. The adjustments to the schedule would not alter the measure's estimated additional $US 200 annual or $US 17 monthly costs for a typical adult in the Sound Transit district.

Sound Transit says that bringing forward completion dates for projects was by far the most frequent theme in the public consultation on the draft plan, which was completed in May.