Train 1513, which left Seattle shortly before 5 p.m., had a medical emergency in Sumner, Sound Transit said in a release.
Crews were at a “train pedestrian accident,” near East Valley Highway and 24th Street East, the East Pierce Fire & Rescue union, IAFF Local 3520 tweeted just before 6 p.m.
A train that left Seattle at 5:12 p.m. was held at Kent Station, and trains scheduled to leave Seattle at 5:42 and 6:12 p.m. were expected to be delayed.
Further details were not immediately available. Check back for updates.