|Locale||Seattle metropolitan area|
|Transit type||Commuter rail|
|Number of stations||12|
|Annual ridership||3,361,317 (2014)|
|Website||Sounder Rider Guide|
|Began operation||September 18, 2000
December 26, 2003 (North Line)
|System length||83 mi (134 km)|
|Track gauge||4 ft 8 1⁄2 in (1,435 mm) (standard gauge)|
Sounder commuter rail (reporting mark SDRX) is a regional rail service operated by BNSF on behalf of Sound Transit. Service operates Monday through Friday during peak hours from Seattle, Washington, north to Everett and south to Lakewood. As of 2011, schedules serve the traditional peak commutes, with most trains running inbound to Seattle in the morning and outbound in the afternoon. Two daily round-trips run the "reverse commute" to and from Tacoma. Additional Sounder trains operate on some Saturdays and Sundays for travel to and from Seahawks and Sounders games at CenturyLink Field and Mariners games at Safeco Field. Both stadiums are a short walk from King Street Station.
The South Line began service with two round trip trains on September 18, 2000 with stops in Tacoma, Sumner, and Auburn that terminated in Seattle. Puyallup and Kent stations were added February 5, 2001; with Tukwila being added March 12, 2001. There are currently nine round trips on the South Line, with two operating in the reverse commute direction. This is the maximum number of trains permitted under Sound Transit's original contract with BNSF, whose tracks the trains run on.
In July 2010, Sound Transit reached a new agreement with BNSF, valued at $185 million, which grants Sound Transit permanent access to the South Line corridor, as well as allowing four more daily round trips to begin, starting in 2012 and continuing through 2015.
The average weekday ridership in 2010 on the South Line was 8,300, down 7% from 2009 due to continued low employment in Downtown Seattle. Since then the average ridership has increased and as of 2013 stood at 9,500 per day 
The 35 miles (56 km) Everett to Seattle line started with a Seahawks Game train on December 21, 2003. Regular service started on the 22nd with one morning train to Seattle and one evening train back. A second round trip train was added on June 6, 2005 to help increased ridership, a third was added in September 2007, and there are now four. There are currently three stops along the North Line: Edmonds, Mukilteo, and Everett. On May 31, 2008 the Mukilteo station opened and trains started stopping at the station.
In September 2008, an additional train was added to the line, bringing the total number to four round trips in the peak direction. Additionally, Sound Transit partners with Amtrak Cascades to allow Sounder riders to use the two trains per day that Amtrak Cascades operates to Bellingham, WA and Vancouver, BC through the RailPlus program. This allows commuters to use the Sounder fare structure between Everett and Seattle. The program is available only to riders who use monthly passes. The Amtrak Cascades trains do not stop at Mukilteo.
Weekday ridership on the North Line was roughly 1,100 in 2010. and remains about the same in 2013. The North line has been prone to frequent cancellation due to mudslides throughout its history  though WSDOT has begun construction to remedy the problem 
Due to the passage of 2008's regional Proposition 1, platform length extensions, up to four additional South Line round trips, and potential stations at Ballard and Broad Street on the North Line are in planning.
Edmonds Station relocation includes a new east platform with larger passenger loading area and weather protected passenger shelter. The parking area will be updated, improved lighting will cover the platforms and parking, secure bike storage will be available and public art is ready for installation. The project will also construct a transit center at the north end of the station to accommodate Community Transit bus service with two passenger shelters and three bus bays. Once a second mainline has been added by the railway in the future, a new west platform will be constructed and the north portion of the east platform will be completed. This project is currently underway and expected to complete in early 2011.
|Model||Manufactured||Road Numbers||Number In Fleet||Notes||Image|
|Bombardier BiLevel Cab Car||1999||101-104||4|
|2000||105-111||7||112-118 sold to Caltrain.|
|Bombardier BiLevel Coach||2000||201-213||13|
|2002||216-218, 227-228, 231-240||15||219-226 & 229-230 sold to Caltrain.|
|Sources (unless noted otherwise):|
|Wikimedia Commons has media related to Sounder commuter rail.|