 The section between Shiraoi and Numanohata is the longest straight railway section in Japan.On 19 November 2016, JR Hokkaido's President announced plans to rationalise the network by up to 1,237 km, or ~50% of the current network, including the proposed conversion to Third Sector operation of the Tomakomai - Iwamizawa section of the Muroran Main Line, but if local governments are not agreeable, the section may face closure.The section between Oshamambe and Numanohata is the part of the main link route between Sapporo and Hakodate.