Tanabe conducted the investigation and directed the construction of the section between Sorachibuto (present day Takikawa City) and Asahikawa City in Kamikawa Line (a part of present-day Hakodate Main Line) in the beginning, and also other sections which later became parts of Soya Main Line and Nemuro Main Line.
田辺は上川線（現函館本線の一部）の空知太（現滝川市）〜旭川市間を手始めに、のちの宗谷本線、根室本線の一部となる区間の調査と建設指揮にあたった。