Sounder South Line

Sounder is a commuter rail system that serves the Seattle metropolitan area in the U.S. state of Washington. Managed by Sound Transit, it uses of tracks, primarily owned by operator BNSF Railway, and runs with equipment maintained by Amtrak. Sounder is split into two lines that intersect at King Street Station in Seattle: the NLine to Everett and the SLine to Tacoma and Lakewood.

Trains typically operate during peak periods, with morning trips to Seattle and afternoon trips to outlying suburbs. Limited mid-day service is offered on the SLine, and both lines offer special weekend trips for sporting events and other major events. Sounder has 12 stations that connect with Link light rail as well as local and regional bus systems. Most also provide park-and-ride facilities, bicycle lockers, and other amenities. Fares are paid using ORCA cards, paper tickets, and mobile ticketing apps, and validated through proof-of-payment checks. In 2024, the system carried a total of 1.88million passengers, or an average of 6,900 on weekdays.

The commuter rail system was preceded by mainline passenger railroad services that began in the late 19th century and two interurban railways that connected Seattle to Everett and Tacoma in the early 20th century. The Municipality of Metropolitan Seattle (now King County Metro) led studies into a modern commuter rail system in the 1980s that were later transferred to the Regional Transit Authority (now Sound Transit), created in 1993. A demonstration service from Everett to Tacoma ran in early 1995, ahead of an unsuccessful ballot measure to fund a regional transit system. A second ballot measure, Sound Move, was passed by voters in November 1996.

Sounder was among the first Sound Transit projects to be launched and construction on its stations began in 1998. The South Line (now the SLine) entered service on September 18, 2000, and was followed by the North Line (now the NLine) on December 26, 2003. Additional trips on both lines were launched in the 2000s after a series of signal and track improvements were completed by Sound Transit and BNSF. The South Line was extended from Tacoma to Lakewood in October 2012 and debuted the first mid-day Sounder trips in 2016. Both lines were rebranded in 2021. An extension of the SLine to DuPont was funded by the Sound Transit 3 package in 2016 and is expected to open in 2045.

Lines

The Sounder commuter rail system comprises two lines that total in length and serve twelve stations. King Street Station in Downtown Seattle is the system's central hub and the terminus of both lines. The NLine (formerly the NorthLine) serves three stations and terminates in Everett; the SLine (formerly the SouthLine) serves eight stations and terminates in Lakewood, with some trips ending in Tacoma. The two lines carried a total of 1.88million passengers in 2024; Sounder was the 13th-busiest commuter rail system in the United States by ridership that year.

Train service is primarily operated during weekday rush hours, with trips inbound to Seattle during the morning and outbound to the suburbs in the afternoon. Other services, including reverse commute and mid-day trips, are offered on the SLine while both lines have occasional weekend service for special events. Most of the Sounder system uses tracks owned by BNSF Railway, which is also contracted to operate the trains. Amtrak provides fleet maintenance and storage of trains at their Seattle facility. The Lakewood–Tacoma segment of the SLine, part of the Point Defiance Bypass, uses tracks that are owned by Sound Transit.

N Line

The NLine begins in Seattle and travels north for on the BNSF Scenic Subdivision towards Snohomish County, where it serves three stations and terminates in Everett. It typically uses short trainsets with two or three passenger cars during its normal four round-trips on weekdays; for special event services, the NLine has five-car trainsets. Trains leave King Street Station and cross beneath Downtown Seattle in the Great Northern Tunnel. The tracks emerge under Pike Place Market and travel through four at-grade crossings along Alaskan Way on the city's waterfront. The NLine continues northwest past Myrtle Edwards Park and under the Magnolia Bridge to traverse the Balmer Yard, a major BNSF railyard in the Interbay neighborhood.

The tracks cross over the Lake Washington Ship Canal on the Salmon Bay Bridge, a movable bascule bridge near the Ballard Locks, and pass through Golden Gardens Park. The NLine continues north along the shore of Puget Sound and passes under overpasses at Carkeek Park in Seattle and Richmond Beach in Shoreline. The coastline tracks run under steep bluffs to the east that range from in height and are prone to landslides during the winter season. The line enters Snohomish County at Woodway and turns northeast at Edwards Point to reach the Edmonds waterfront. Its first outbound station is Edmonds station, located adjacent to the city's ferry terminal and downtown.

The NLine continues north along Puget Sound until it reaches Mukilteo Lighthouse Park, where the tracks turn east and cross under State Route 525. Trains then stop at Mukilteo station, a two-platform station near a ferry terminal that serves the Whidbey Island ferry. The tracks continue northeast along Possession Sound and pass several public beaches before they reach Everett. The NLine travels east under Downtown Everett in a short tunnel and turns south to reach its terminus at Everett Station, a multimodal hub with bus and Amtrak connections. Trains take approximately 53minutes to travel from Seattle to Everett and have views of Puget Sound, the Olympic Mountains, and Mount Baker.

S Line

The SLine is long and travels south along the State Route 167 corridor from Seattle to Pierce County, where trips terminate in either Tacoma or Lakewood. It follows portions of the BNSF Seattle Subdivision from Seattle to Tacoma, a Tacoma Rail spur, and Sound Transit's Lakewood Subdivision from Tacoma to Lakewood. The SLine uses longer trainsets in five-car and seven-car configurations and has 13 round trips on weekdays—including reverse direction trips and limited mid-day service. Trains begin at King Street Station and travel south along the east side of Lumen Field and T-Mobile Park, passing under the retractable roof of the latter, in the industrial SoDo neighborhood. The tracks pass the Sounder and Amtrak maintenance facility near South Holgate Street and continue under the Spokane Street Viaduct; they then turn southeast at Union Pacific's Argo Yard.

The line travels southeast through Georgetown and runs between Boeing Field to the west and Interstate 5 to the east. The SLine crosses under the tracks for the 1Line of the Link light rail system near South Boeing Access Road and continues into Tukwila. The tracks cross under Interstate 5 and begin to follow the Duwamish River