High Quality Content by WIKIPEDIA articles! Link Light Rail is a light rail transit system serving the Seattle metropolitan area area. The system is operated by Sound Transit, a transit agency formed by King, Pierce, and Snohomish counties. Sound Transit opened the first Link segment in 2003, the light rail/streetcar line Tacoma Link. The higher-capacity Central Link line opened in Seattle on July 18, 2009. Future extensions are planned throughout the three-county area.