hanko is the southernmost town in finland. hanko has a seaport which, thanks to its location, can be used for the longest possible time during the sometimes very severe, and freezing, finnish winters. because all the other finnish seaports might be frozen solid during the winter, there was an anticipation for a large amount freight transit traffic. as such, a decision was made to privately fund the railway from hanko to the finnish state railways' helsinki–hämeenlinna line, with the connection at hyvinkää.