Update, 9:41 a.m. Sunday, Aug. 2: Sound Transit announced that trains have resumed normal operation.

Original post: Link light rail trains are not running between downtown and the University of Washington, the result of an unspecified mechanical issue found during a planned “system upgrade” Sunday morning, Aug. 2. Sound Transit does not know when trains will be running again, a spokesperson said.

Trains were scheduled to be out of service between 5:45 a.m. to 8 a.m. Sunday. Just after 8:20 a.m., Sound Transit announced the stoppage would extend into the morning. Free Link shuttle buses are running every 30 minutes from each station. Riders should leave additional time for their trips, Sound Transit said on its website.

Trains are operating between Stadium and Angle Lake stations.