Over the weekend, Sound Transit trains were halted or slowed six times on the network’s busiest section, between Shoreline South/148th and University of Washington stations. The disruptions lasted about four hours in total. They were caused by a malfunction at a high-voltage substation near Northgate Station.
The protection system detected a problem and automatically shut down other substations to protect equipment from damage. This setup leaves the network vulnerable: a failure in one place can stop trains nearby. Engineers are investigating what caused the communications problem; there is no timeline yet for releasing their findings. Ultimately, technicians isolated the Northgate substation so the others could supply power without shutting down automatically. At times, passengers were carried by shuttle buses.
The disruption affected more than just northbound trains. Two Link routes—the Seattle region’s light rail system—share a section between downtown and Lynnwood: their lines converge and run on the same tracks, through shared stations and the downtown tunnel. As a result, problems or capacity restrictions on this section can delay trains on both routes.
A malfunction near the University of Washington can also affect service. Eastside trains, which connect the eastern part of the metropolitan area with Seattle, cross Lake Washington on railroad tracks on the I-90 bridge, after which their route connects with the line near the university. On Saturday, Eastside trains were turned back at Judkins Park Station to prevent trains from bunching up in the tunnel.
The failure came as Sound Transit works to improve the network’s reliability. After major disruptions in 2024, the agency stepped up maintenance and introduced scheduled overnight closures to repair tracks and electrical systems. In the first four months of 2026, unplanned service interruptions averaged eight hours per month—below the 10-hour limit and well under the 2024 average of 36 hours. In July, trains arrived on time 86% of the time, short of the 90% target; power reliability also fell slightly short of plan.
The Link network carries about 170,000 people a day. On Sunday, service was fully restored shortly after the Seattle Seahawks beat the Kansas City Chiefs 20–3—just in time for fans leaving the stadium.
Based on: What caused light rail’s latest round of power breakdowns