Trains will run every 15-20 minutes from 7 p.m. - 1 a.m. until Dec. 30. Normally, trains run every 10 minutes until 10 p.m., and every 15 minutes from 10 p.m. to 1 a.m. weekdays. No work will occur on Sunday nights or Dec. 25 - 27. Trains will operate on regular schedules those days.
Contractors will grind the surface of the rails with machinery mounted on a railcar that slowly travels up and down the tracks. The work will start after 7 p.m. and may continue till 4 a.m. Grinding along the section of tracks in the Rainier Valley is expected to take up to a week.