When the 220 metre long tunnel is completed, it will greatly facilitate access to station platforms and cycling around the station.  The "Kaisatunneli" will be 8 meters wide and 3 meters high. The width of the bike lane is 4 meters and the pedestrian lane is 3.5 meters. There will also be a bicycle center owned by the City of Helsinki Transport Authority (HKL) and bicycle parking for 900–1000 bicycles.

https://www.stadinraksat.fi/helsingin-paarautatieaseman-pyoraily-ja-jalankulkutunnelin-valmistelevat-tyot-kaynnistyvat/