3 Line (Sound Transit)

{{Short description|Future light rail line in Seattle, Washington, U.S.}}

{{Use American English|date=February 2025}}

{{Infobox rail line

| box_width =

| name = 3 Line

| other_name =

| color = {{rcr|Sound Transit|3 Line}}

| logo = Line 3 (Sound Transit) icon.svg

| logo_width = 35px

| logo_alt =

| image =

| image_width =

| image_alt =

| caption =

| type = Light rail

| system = Link light rail

| status = Planned

| locale = Seattle metropolitan area, Washington, US

| start = Everett Station (north)

| end = {{stn|Alaska Junction}} (south)

| stations = 25 (9 new, 1 provisional)

| daily_ridership =

| ridership2 =

| planopen = 2032 (West Seattle)
2037 (Southwest Everett)
2041 (Downtown Everett){{cite web |title=Everett Link Extension: Timeline and milestones |url=https://www.soundtransit.org/system-expansion/everett-link-extension/timeline-milestones |publisher=Sound Transit |accessdate=September 4, 2024}}

| owner = Sound Transit

| operator =

| character = Underground, elevated, and surface

| depot =

| stock =

| linelength_mi =

| tracks = 2

| gauge = {{Track gauge|ussg|allk=on}}

| electrification = {{1,500 V DC|conductor=overhead}}

| speed = {{convert|55|mph}}

| website =

| map = {{3 Line (Sound Transit)|inline=y}}

| map_state = collapsed

}}

The 3 Line (colored magenta) is a future light rail line in the Seattle metropolitan area in the U.S. state of Washington, to be part of Sound Transit's Link light rail system. It is planned to connect Everett and Snohomish County to Downtown Seattle and West Seattle. The 3 Line would share tracks with the 2 Line from southern Everett to International District/Chinatown station along the 1 Line corridor.{{cite map |date=August 2024 |title=Sound Transit future service |url=https://www.soundtransit.org/sites/default/files/documents/st-future-service-map.pdf |publisher=Sound Transit |accessdate=September 4, 2024}}

The line is planned to reuse existing tracks that are part of the 1 Line and its future expansions; the 1 Line will then be rerouted through a new Downtown Seattle tunnel to be built for the Ballard Link Extension.{{cite web |date=February 2022 |title=2022 Progress Report |url=https://www.soundtransit.org/system-expansion/progress-report |publisher=Sound Transit |accessdate=January 2, 2023}} The {{convert|16.3|mi|km|adj=mid}} Everett Link Extension to the north of Lynnwood will have six stations and is scheduled to open between 2037 and 2041.{{cite news |last=Watanabe |first=Ben |date=December 8, 2021 |title=City of Everett outlines light rail priorities for 2037 |url=https://www.heraldnet.com/news/city-of-everett-outlines-light-rail-priorities-for-2037/ |work=The Everett Herald |accessdate=January 2, 2023}} The {{convert|4.7|mi|km|adj=mid|-long}} West Seattle Link Extension will include three new stations southwest of SODO station and is scheduled to open in 2032.{{cite web |date=August 2022 |title=West Seattle and Ballard Link Extensions: Expanding light rail in Seattle |url=https://www.soundtransit.org/sites/default/files/project-documents/west-seattle-ballard-project-overview.pdf |publisher=Sound Transit |accessdate=January 2, 2023 |archive-date=September 17, 2017 |archive-url=https://web.archive.org/web/20170917051725/https://www.soundtransit.org/sites/default/files/project-documents/west-seattle-ballard-project-overview.pdf |url-status=dead }} The 3 Line was created as part of the Sound Transit 3 program, approved by voters in 2016, which included both projects.{{cite news |last=Lindblom |first=Mike |date=October 24, 2019 |title=Pricier light-rail tunnels into Ballard and West Seattle fall by the wayside |url=https://www.seattletimes.com/seattle-news/transportation/450m-central-ballard-light-rail-tunnel-falls-by-the-wayside/ |work=The Seattle Times |accessdate=January 2, 2023}}

The West Seattle Link Extension would include a high bridge crossing the Duwamish River adjacent to the existing West Seattle Bridge. In 2024, Sound Transit and HNTB proposed a cable-stayed bridge design that would be {{convert|1,690|ft|m}} long and have two towers that are {{convert|374|ft|m}} tall.{{cite news |last=Miller |first=Brian |date=August 19, 2024 |title=Behold! Sound Transit shows 'diamond pylon' span over Duwamish |url=https://www.djc.com/news/re/12165404.html |work=Seattle Daily Journal of Commerce |accessdate=September 4, 2024}} The western end of the line would be tunneled between Alaska Junction and Avalon stations, where trains would begin to use an elevated guideway.{{cite news |last=Newcomb |first=Tim |date=October 30, 2024 |title=Sound Transit Finalizes West Seattle Link Extension Alignment |url=https://www.enr.com/articles/59632-sound-transit-finalizes-west-seattle-link-extension-alignment |work=Engineering News-Record |accessdate=December 2, 2024}} The Federal Transit Administration issued their preliminary approval for the project via a record of decision in April 2025.{{cite news |date=May 1, 2025 |title=Another step forward for West Seattle Link |url=https://www.djc.com/news/ae/12169695.html |work=Seattle Daily Journal of Commerce |url-access=subscription |accessdate=May 3, 2025}} The project is expected to cost $6.7 to $7.1 billion to construct and carry 26,000 daily passengers.{{cite news |last=Lindblom |first=Mike |date=November 12, 2023 |title=West Seattle's light-rail path finally takes shape, at a price |url=https://www.seattletimes.com/seattle-news/transportation/west-seattles-light-rail-path-finally-takes-shape-at-a-price/ |work=The Seattle Times |accessdate=September 4, 2024}}{{cite news |last=Lindblom |first=Mike |date=September 18, 2024 |title=West Seattle's light rail estimate soars past $6 billion |url=https://www.seattletimes.com/seattle-news/transportation/west-seattles-light-rail-estimate-soars-past-6-billion/ |work=The Seattle Times |accessdate=December 2, 2024}}

The Everett Link Extension includes a new operations and maintenance facility that is scheduled to open in 2034 at one of three sites near Paine Field and the Boeing Everett Factory.{{cite web |date=September 2023 |title=Everett Link Extension fact sheet |url=https://www.soundtransit.org/sites/default/files/documents/EVLE-project-fact-sheet-english.pdf |publisher=Sound Transit |accessdate=September 4, 2024}} The project is estimated to cost between $5.05 billion and $6.9 billion and open either as a single phase in 2037 with its funding shortfall addressed in two phases from 2037 to 2041.{{cite news |last=Lindblom |first=Mike |date=June 23, 2023 |title=Sound Transit charts its long light-rail journey to Everett |url=https://www.seattletimes.com/seattle-news/transportation/sound-transit-charts-its-long-light-rail-journey-to-everett/ |work=The Seattle Times |accessdate=September 4, 2024}}