HDR will support the Central Puget Sound Regional Transit Authority (Sound Transit) in planning the final extension needed to complete light rail service between Seattle and Tacoma, Wash. The Tacoma Dome Link Extension (TDLE) project will advance a reliable transit alternative to severely congested roadways in the South Sound corridor.

Sound Transit’s board of directors authorized a contract with HDR’s team to provide planning, preliminary engineering, environmental, and public involvement services. HDR will support the 9.7-mile light rail transit extension with four new transit stations and a new operations and maintenance facility.

The TDLE project will continue south from Sound Transit’s previous light rail project, the Federal Way Link Extension (FWLE). Service on the TDLE project is expected to begin in 2030. The alignment will continue through South Federal Way, Fife, East Tacoma, and it will terminate near the Tacoma Dome transit hub, with connections to the Tacoma Link urban rail transit system, Amtrak, and Sounder commuter rail service.

“With four new LRT stations, Sound Transit and the cities in the corridor will have a once-in-a-generation opportunity to transform station areas into vibrant new station-communities,” HDR Project Manager Sharon Kelly said. “While Sound Transit has defined a representative alignment and general station locations, we will help them refine both in ways that benefit these cities for generations.”

Public involvement will dominate planning activities for the next three years. HDR’s team will lead stakeholder engagement, inviting the public, and property and business owners, to weigh in along with four municipalities, three transportation agencies, two counties and one tribal government. The TDLE alignment also will pass through natural resource lands, crossing streams and the Puyallup River, bringing the first urban rail transit stop to Puyallup Tribe of Indians' lands.

Among the project’s first challenges will be finding a site for a new Link operations and maintenance facility, which is needed for this project and the larger Link system to store and maintain light rail vehicles. HDR’s recent acquisition, HDR | Maintenance Design Group, brings unique qualifications to plan and design a custom, purpose-built facility that’s embraced by the community around it.