Before the
Pacific War, there were plans to develop the northern part of Shiranuka with an east-west line that would have connected Mashū on the
Senmō Main Line with
Ashoro on the
Chihoku Line. In 1952, planning began instead for a line running from south to north in the Charo Valley, which was also listed in the appendix of the revised Railway Construction Law the following year. Along the planned route, there were 64,000 hectares of forest resources and deposits of around 320 million tons of high-quality
hard coal. Several mining companies opened mines, but the mined coal had to be transported away by truck, which caused higher costs and made it difficult to increase production. Construction work on the railroad line began in June 1958, but progress was rather slow. On October 7, 1964, the
Japan National Railway opened the 25.2 km section from
Shiranuka Station to
Kami-Charo Station. The mine located there was then able to expand its production capacity to the maximum. Almost all the coal was now transported by rail. However, the planned replacement of
rafting by freight trains did not materialize and timber was transported by truck instead. On September 8, 1972, the line was extended by 7.9 km from Kami-Charo to Hokushin. The original plan was to connect the Shiranuka Line ending in Hokushin with the
Aioi Line at
Kitami-Aioi, which would have required the construction of a 5.2 km long tunnel, among other things. The corresponding project was approved in August 1967. A youth holiday camp provided additional passenger traffic with special trains during the summer season, However, it became apparent that the line would be closed because it had a very low cost recovery ratio outside the season. Based on the law passed in 1980 to restructure the state railway finances, the state railroad and city authorities agreed to replace the railroad line with a bus line. The closure took place on October 23, 1983. == Stations ==