The rules are simple. If a mudslide hits the BNSF Railway mainline between Seattle and Everett, passenger trains have to stop rolling for 48 hours, providing there are no additional slides within that window.
It’s done for safety reasons. Gus Melonas of BNSF Railway says while freight traffic is still allowed to move when passenger trains do not, that only comes after the unstable slope has been inspected by geo-techs. And then those freight trains only move at restricted speeds.