Hakodate Main Line connected Sapporo, the capital city of Hokkaido, and Hakodate, gateway city from Honsyuu to Hokkaido. The line could be separated in two sections that have quite different characteristics. The seaside and mountain sections. The seaside section was busy as a part of major traffic route between Sapporo and Hakodate together with Muroran Main Line with double track arrangement. The mountain section was not so busy and rather a sort of local line with single track. The condition of the mountain section was quite severe with steep grade and heavy snow fall in winter. The snow hight of 3m in winter was quite common. There is no wonder why this area has famous ski resort “Niseko.”