Link Light Rail in Seattle#

Link light rail is the backbone of the Puget Sound region’s transit system, operated by Sound Transit. As of early 2026, the system has three lines, 48 stations, and approximately 55 miles of track. Link is the 4th-highest ridership light rail system in the United States. (The Urbanist)

Current system#

1 Line (Lynnwood – Federal Way)#

The 1 Line is the original and busiest line. It runs 41 miles through 26 stations, connecting Lynnwood City Center in Snohomish County to Federal Way Downtown in south King County. Key stops include Northgate, the University District, Capitol Hill, downtown Seattle (Westlake, Symphony, Pioneer Square), the International District, Beacon Hill, the Rainier Valley, SeaTac Airport, and Federal Way. Service runs approximately every 6 minutes at peak. (Sound Transit 1 Line)

2 Line (Downtown Redmond – Lynnwood via Seattle)#

The 2 Line currently operates 10 stations on the Eastside from South Bellevue to Downtown Redmond. On March 28, 2026, the cross-lake segment opens, extending the 2 Line across the I-90 floating bridge – the first light rail line on a floating bridge anywhere in the world – with new stations at Mercer Island and Judkins Park. The 2 Line will then run from Redmond to Lynnwood, sharing tracks with the 1 Line north of International District/Chinatown. Combined headways between Lynnwood and downtown Seattle will be approximately every 4 minutes. (The Urbanist)

T Line (Tacoma)#

The T Line is a streetcar-style line connecting downtown Tacoma, the Hilltop neighborhood, and Tacoma Dome Station.

Infrastructure#

Link light rail uses a mix of tunnels, elevated guideways, at-grade surface segments, and a floating bridge crossing. Understanding the physical infrastructure helps explain the system’s operating characteristics, speed variations, and expansion challenges.

Tunnels#

Link has four major tunneled segments totaling roughly 14 miles of twin-bore tunnel.

Downtown Seattle Transit Tunnel (DSTT). The 1.3-mile Downtown Seattle Transit Tunnel runs west under Pine Street and south under 3rd Avenue, serving four underground stations: Westlake, Symphony (formerly University Street), Pioneer Square, and International District/Chinatown. Originally built in 1987-1990 as a bus tunnel by King County Metro, it was retrofitted for joint bus-and-rail operations in 2005-2007 at a cost of approximately $94 million. Buses and trains shared the tunnel from 2009 to 2019, when it became rail-only. The DSTT has a theoretical capacity of 40 trains per hour per direction with 90-second headways.

Beacon Hill Tunnel. A roughly one-mile twin-bore tunnel passes under Beacon Hill between SODO and the Rainier Valley. The tunnel was bored by a 360-ton Mitsubishi tunnel boring machine nicknamed the “Emerald Mole,” featuring a 21-foot-diameter cutterhead. Launched in January 2006, it completed the first 4,300-foot tube in May 2007 and the second in March 2008, emerging within 5 millimeters of its target. Beacon Hill station sits 160 feet underground, making it the system’s deepest station, accessed by four high-speed elevators from two shafts excavated to 185 feet. (Sound Transit)

University Link Tunnel. The 3.15-mile tunnel connects the DSTT to the University of Washington via Capitol Hill station. Three tunnel boring machines excavated 21-foot-wide tunnels from 2009 to 2012: two Herrenknecht machines named Balto and Togo (launched from UW station southward) and a Hitachi Zosen machine named Brenda (launched from Capitol Hill toward downtown). The tunnel reaches 300 feet below the surface under Volunteer Park and passes just 15 feet beneath Interstate 5 and the Montlake Cut. The extension opened in March 2016, six months early and $200 million under its $1.9 billion budget. (Sound Transit)

Northgate Link Tunnel. The 3.5-mile twin-bore tunnel extends from the University of Washington to Northgate, passing beneath the Lake Washington Ship Canal. Two 600-ton tunnel boring machines with 21.5-foot cutterheads bored the tunnels from 2014 to 2016, mining 20-40 feet per day at depths of 60 to 140 feet. The tunnel serves Roosevelt and U District stations. The extension opened in October 2021 and cost $1.9 billion. (Sound Transit)

A second downtown transit tunnel is planned as part of the Ballard Link Extension (ST3), with six new underground stations. This tunnel is needed because the existing DSTT will reach capacity with two lines operating at peak frequency.

Bridges and elevated segments#

I-90 Floating Bridge crossing. The 2 Line crosses Lake Washington on the Homer M. Hadley Memorial Bridge, a 1.1-mile floating span built in 1989 with provisions for future light rail in its center express lanes. This is the first light rail line on a floating bridge anywhere in the world. Engineers designed a specialized “track bridge” system to accommodate six degrees of motion from changing lake levels, wind, waves, and traffic loading. Rails rest on approximately 9,000 lightweight concrete blocks attached to the bridge deck with a shock-absorbing material called corkelast, held in place by polymers that require no drilling into the deck. The blocks and polymers were tested at the University of Washington, and the track bridge prototypes were validated at the Transportation Technology Center in Pueblo, Colorado at speeds up to 55 mph. Popular Science named the floating bridge rail technology one of the most important engineering innovations of 2017. A cathodic protection system prevents stray electrical current from corroding the bridge’s steel anchor cables. (Sound Transit)

I-405 bridge. An 810-foot bridge carries the 2 Line across Interstate 405 in Bellevue, connecting the Bellevue Downtown and Wilburton stations.

Structure C (Federal Way Link Extension). A 1,100-foot cast-in-place balanced cantilever bridge carrying the 1 Line over the McSorley Creek wetland in Kent, south of the former Midway Landfill. Its 500-foot central span is the longest in the Link light rail system. In July 2022, a landslide near South 259th Place revealed that soil conditions were far more unstable than predicted, forcing a redesign from the original column-supported plan. Two sets of twin piers anchored 110 feet deep in glacial soil support the bridge, which is post-tensioned with approximately 103 miles of internal steel cables. The structure incorporates seismic bearings that allow the deck to slide during earthquakes and shock transmission units at the end piers that lock up under seismic loading to share forces with the main piers. Designed to withstand a 2,500-year earthquake event, the bridge added roughly $110 million and two years to the Federal Way Link Extension schedule. (Sound Transit | The Seattle Times)

Elevated guideways. Significant elevated segments include the guideway through SODO and Tukwila, the approach to SeaTac Airport, the Lynnwood and Federal Way extensions, and the Eastside guideway through South Bellevue. The elevated alignment north of Northgate carries the 1 Line to Lynnwood City Center.

At-grade segments#

The 1 Line runs at-grade for 4.5 miles in the median of Martin Luther King Jr. Way South through the Rainier Valley, serving Columbia City, Othello, and Rainier Beach stations. This segment has 28 signalized crossings with partial gates where trains share the right-of-way with vehicles, cyclists, and pedestrians. The at-grade alignment was a cost-saving decision in the original Sound Move plan; other parts of the system are tunneled or elevated. Since 2009, this stretch has been the site of 136 collisions between trains and vehicles, people, or objects. Sound Transit is spending $14-21 million to add pedestrian gates at Columbia City and Othello stations by mid-2026. Sound Transit has stated that all future Link extensions will be grade-separated (elevated or tunneled). (The Urbanist)

Light rail vehicles#

Sound Transit operates two generations of light rail vehicles on the 1 and 2 Lines, plus a smaller fleet on the T Line.

Series 1 (Kinkisharyo). The original fleet of 62 low-floor vehicles, manufactured by Kinkisharyo in Japan and assembled in Everett, Washington. Each car is 95 feet long, 70% low-floor, with 74 seats and a crush-load capacity of 252 passengers. Delivered in three orders from 2006 to 2011 at approximately $4.2 million per unit.

Series 2 (Siemens S700). Sound Transit awarded Siemens Mobility a $554 million contract in 2016 for 122 S700 low-floor vehicles, later expanded to 162. Each car is approximately 95 feet long with 74 seats (70 in some configurations), larger windows, a wider center aisle, four bicycle hooks (twice the Series 1), dynamic passenger information displays, and LED lighting. Assembled at Siemens’ plant in Sacramento, California, the first entered service in May 2021. The Series 2 vehicles are not compatible for coupled operations with Series 1 cars; trains are composed entirely of one type or the other. (Sound Transit)

Series 3 (future). Sound Transit plans to procure approximately 236 additional vehicles through a competitive bid process to support ST3 extensions. The first Series 3 vehicles are expected to enter service around 2032.

Operating characteristics. Trains run at up to 55 mph in tunnels and on elevated segments and 35 mph on surface sections. Revenue service uses two-car, three-car, or four-car consists depending on demand. The system runs on 750V DC overhead catenary power. As of early 2026, the total fleet across all lines is approximately 226 vehicles.

Operations and maintenance facilities#

Sound Transit maintains its fleet at Operations and Maintenance Facilities (OMFs) — large rail yards where trains are stored, cleaned, inspected, and repaired.

OMF Central in SODO has served the fleet since the system opened in 2009. OMF East in Bellevue’s Spring District opened in 2024 to support 2 Line operations and includes a transit-oriented development component with planned housing, retail, and office space on 6.9 acres. OMF South in Federal Way will include a 1.4-mile connecting track from the mainline and a 24-hour vehicle testing track; it is expected to create over 610 jobs with an average wage of $45/hour. (Sound Transit)

Link light rail timeline#

1996: Sound Move (ST1) approved#

Voters approved the region’s first major transit investment package, authorizing $3.9 billion for Link light rail from downtown Seattle to SeaTac Airport, along with Sounder commuter rail and ST Express bus service. The Central Puget Sound Regional Transit Authority (later renamed Sound Transit) had been created by the state legislature in 1993. (Sound Transit History)

2008: Sound Transit 2 approved#

Voters approved $13.5 billion in capital projects (ST2) to extend light rail to Lynnwood, Redmond, and Federal Way, expanding the system from 14 to 55 miles. A similar measure had failed in 2007. (Sound Transit 2)

2009: Link light rail opens#

Central Link light rail began revenue service on July 18, 2009, running 14 miles from Westlake station in downtown Seattle to Tukwila International Boulevard. SeaTac Airport station opened later that year in December. (Sound Transit)

2016: Landmark year for Link expansion#

• March: Capitol Hill and University of Washington stations opened, the first northward expansion of Link
• September: Angle Lake station opened, extending the 1 Line south
• November: Voters approved Sound Transit 3 (ST3), a $54 billion package authorizing 62 more miles of light rail to Ballard, West Seattle, Tacoma Dome, Everett, and the Eastside. It was the largest transit investment in the region’s history. (Sound Transit ST3)

2021: Northgate Link Extension#

Three new Link stations (Northgate, Roosevelt, U District) opened in October 2021, connecting north Seattle and triggering the first of several major bus network restructures feeding light rail.

2024: Rapid Link expansion#

• April: The 2 Line opened its initial Eastside segment from South Bellevue to Redmond Technology, bringing light rail to the Eastside for the first time
• August: Lynnwood Link Extension opened with 4 new stations, extending the 1 Line into Snohomish County
• August: Sound Transit introduced a $3 flat fare on Link, replacing the previous distance-based system. Tap-off was eliminated.
• October: Link set an all-time monthly ridership record of 3.08 million boardings. (The Urbanist)

2025: Continued growth#

• May: 2 Line extended to Downtown Redmond with two new stations (Marymoor Village, Downtown Redmond)
• December: Federal Way Link Extension opened with 3 new stations (Kent Des Moines, Star Lake, Federal Way Downtown), extending the 1 Line by 7.8 miles

2026: Cross-lake connection#

On March 28, 2026, the 2 Line extends across the I-90 floating bridge to Seattle, adding Mercer Island and Judkins Park stations. The 2 Line will then operate from Downtown Redmond to Lynnwood City Center via downtown Seattle. A Pinehurst infill station (NE 130th Street) is also expected to open in 2026. (Sound Transit)

For a timeline of other regional transit milestones (Sounder, streetcars, BRT, monorail), see the Mass Transit guide.

Future expansion#

Sound Transit is building several major extensions under the ST3 program, though timelines and budgets have shifted significantly since the 2016 vote due to inflation, construction cost increases (71.5% since 2020), and pandemic-related revenue shortfalls. A $20-25 billion affordability gap was announced in August 2025. (The Urbanist)

At full build-out, the Link system is projected to have approximately 116 miles, 70 stations, and 5 lines serving Everett to Tacoma with branches to Redmond, Ballard, and West Seattle.

For planned Stride BRT and RapidRide expansions, see the Mass Transit guide.

How Sound Transit funds expansion#

Sound Transit’s capital program is funded primarily through three voter-approved tax packages:

• Sound Move / ST1 (1996): $3.9 billion for initial Link, Sounder, and ST Express
• Sound Transit 2 (2008): $13.5 billion in capital projects for Link extensions to Lynnwood, Redmond, and Federal Way
• Sound Transit 3 (2016): $54 billion for Ballard, West Seattle, Tacoma Dome, and Everett extensions plus Stride BRT

These packages are funded by a combination of sales tax (currently 1.4% across the Sound Transit district), motor vehicle excise tax, and property tax (up to 25 cents per $1,000 assessed value). Between 1996 and 2023, the three packages generated over $21.8 billion in tax revenue. (Sound Transit Funding)

Data sources#

• Sound Transit Ridership Tracker: Interactive dashboard with Link, Sounder, and ST Express ridership trends
• Sound Transit System Expansion: Official project tracker for all voter-approved expansion projects

Key statistics#

Sources: Sound Transit Ridership Tracker | The Urbanist

Related resources#

• Mass Transit – Buses, commuter rail, streetcars, ferries, and how the region funds and plans transit
• Micro Mobility – E-scooters, bike share, and first/last-mile transit connections
• Bike Network – Protected bike lanes, neighborhood greenways, and trails connecting to transit
• Transportation Glossary – Terms like “RapidRide,” “TOD,” “ST3,” and “mode share”
• Sound Transit System Expansion – Official project tracker for all voter-approved expansion projects

Last updated: February 2026