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 thirteen round trips on the South Line, with three operating in the reverse commute direction. 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 2017. On October 8, 2012, the extension to South Tacoma and Lakewood stations were inaugurated, with five daily round trips, all of which are in the peak direction, serving the new stations. In September 2016, a mid-day round trip was added between Lakewood and Seattle. In September 2017, two additional round trips were added, bringing the total to eight daily round trips servicing the Lakewood extension. 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 October 2015 stood at 14,500 per day. In 2019, South Line ridership was 16,419 per day.
North Line
The 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 increase ridership, a third was added in September 2007. In September 2008, an additional train was added to the line, bringing the total number to four round trips in the peak direction. On May 31, 2008, service to Mukilteo station began. There are currently three stops along the North Line: Edmonds, Mukilteo, and Everett. 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 nor does Amtrak's Empire Builder from Chicago, Illinois. Weekday ridership on the North Line was roughly 1,100 in 2010 and was about 1,561 in the first quarter of 2016. Trains on the North Line have been prone to frequent cancellation due to mudslides throughout its history, though WSDOT has begun construction to remedy the problem.
Future expansion
Sound Transit plans to add additional Sounder South Line stations at Tillicum and DuPont. The track has already been constructed by Sound Transit with funding from WSDOT as part of the Point Defiance Bypass project. The construction of the stations will be funded by the Sound Transit 3ballot measure passed in 2016. The two stations are expected to open in 2036 and cost $300 million. In addition, Sound Transit plans to extend station platform lengths on the south line to accommodate trains up to ten cars in length, up from the current seven.
Fares
As with Link light rail, Sounder operates using a proof-of-payment fare system and uses distance-based fares. Passengers are required to purchase a paper ticket, use a mobile ticket, or tap their ORCA card before boarding trains. Sound Transit fare inspectors or police officers randomly board trains and check for valid proof-of-payment, issuing warnings or fines to passengers without valid proof-of-payment. Passengers using ORCA cards are charged the maximum fare from the station they are traveling from and are issued a permit to travel when they tap before boarding and, if necessary, receive a refund when they tap after boarding. Discounted fares are offered for youth, seniors and the disabled, and low-income riders qualifying for the ORCA Lift program. During the COVID-19 pandemic in 2020, fare collection for all Sound Transit services was suspended from March 21 to June 1. Fares on Link and Sounder were reintroduced on June 1 with a discounted rate of $2 for non-ORCA users on Sounder.
