 Another project under the five-year plan was a railway between Yemi on the Hambaek Line and Jeongseon.The section climbing the mountains around Hambaek to Jeongsan (renamed Mindungsan in 2009), which would later become part of the Taebaek Line, was completed on December 19, 1966, and the entire railway from Jecheon to Jeongseon was renamed the Jeongseon Line, with the short Yemi–Hambaek branch retaining the Hambaek Line name.A long track section on the climb after Yemi is the steepest on South Korea's network at 30.3‰.