During the examination of the route of the railroad over Usui-toge Pass, there were various proposed ideas including steep line going through the spot from 25‰ to 100‰, loop line, switchback, and cable car.
碓氷峠を越える鉄道建設ルートの検討では、25‰から100‰にも達する急勾配線、ループ線、スイッチバック、ケーブルカーなどが候補に挙がっていた。