In fact, survey began and construction started in some areas but mountainous terrains such as Usui-toge Pass presented more serious challenge than anticipated thereby various setbacks such as work delays, cost overrun and transport capacity restriction after the opening became inevitable.
実際に測量が開始され、一部では建設にも着手したが、碓氷峠などの山越えが予想以上に険しく、工事の長期化や費用増、開業後の輸送力制限などが避けられなくなった。