Late night trains weren't running between the Edmonds Station and the Waterfront Station and people had to take buses, temporarily put in place to bridge the gap in the SkyTrain system.
TransLink blamed the service interruption, which began a little after 11 p.m. PT, on a fire on the Expo Line guideway, which caused a communications failure.
TransLink wouldn't say what caused the fire, or exactly where it occurred along the Expo Line.
The transit company said nobody was stranded on the tracks, and neither the Millennium Line, nor the Canada Line were affected.
Many transit users took to social media to express their frustration with the delays.
TransLink wouldn't say whether Friday morning commuters could expect similar delays.