The Stockholm City commuter train station, which is located more than 40 metres underground, was evacuated shortly before 2pm after a fire in a technical room.
The fire was quickly extinguished, but it caused a lot of smoke which made public transport operator SL decide to evacuate.
The blaze started when dust and lint ignited during renovation work on escalators, emergency control room officer Göran Norman told newswire TT, and police said no crime had been committed.
The station was reopened around an hour later, but SL warned that there would be knock-on delays and cancelled trains.
Stockholm's central metro train station T-centralen and the central train station for long-distance trains above ground were not affected.