Beware that half of the trains from the airport to city center ends in Pasila from this Sunday 24th and you have to change to get to the main station. P is the train ending in Pasila, but I is still a direct train. Changes of course also from Helsinki/Pasila to the airport. This is due to rail works and begins Sunday, June 24 and lasts with some modification(P and I changes places) until Aug 5. Pretty confusing.