Spokesman Gus Melonas says crews will have the mud, rocks and tree debris cleared later in the morning, so freight trains can continue to roll.
But Amtrak and Sounder commuter trains will have to observe at 48-hour safety moratorium until Saturday morning. Passengers can be bused.
Melonas says this is the seventh blocking event on the tracks north of Seattle this season, compared to 60 last season. The railroad has invested in slide prevention, clearing ditches and installing motion monitors along the stretch of tracks that run along Puget Sound under a bluff.