Arup has been named the lead designer for Sound Transit's new Operations and Maintenance Facility (OMF) South in the Seattle region. The Sound Transit Board approved a $350 million progressive design-build contract for the 70-acre hub, which will be delivered by Hoffman Construction Company alongside Arup and owner Sound Transit.

Project Scope and Regional Infrastructure
The new facility will be located at South 336th Street in Federal Way. It is designed to house maintenance and operations equipment, as well as staff, to accommodate the expansion of the regional light rail vehicle fleet. The infrastructure project is a key component in preparing for the planned Tacoma Dome Link Extension and establishing operational resilience for Sound Transit's expanding footprint.

The OMF South will feature dedicated space to store, test, commission, and maintain a minimum of 72 new 190-foot-long Series 3 light rail vehicles. The site layout also incorporates a maintenance-of-way building along with multiple operational support facilities. Upon its scheduled completion in 2032, the facility is projected to employ more than 600 people to support long-term transit operations across the region.

Progressive Design-Build Delivery Method
This contract represents Sound Transit’s initial utilization of a progressive design-build procurement model. Under this project delivery framework, the owner, designer, and contractor collaborate during the early phases of development to jointly establish the design, total cost, and construction schedule. This early alignment is intended to manage project uncertainty, minimize subsequent costly alterations, and streamline the execution of the complex technical scope.

The project team has been authorized to initiate Phase 1 project definition. This initial phase encompasses:

Arup and Hoffman will maintain a close partnership with Sound Transit through the final design stages and early construction activities as the development progresses.

Alignment and Operational Positioning
The project leverages a history of transit infrastructure delivery in the region, focusing on technical excellence and close inter-agency collaboration to deliver essential public works.

Edited by Romila DSilva, Induportals Editor, with AI assistance.