The first railway along a section of what became the Jeolla Line was the
Zenboku Lightrail Line, a narrow gauge line from
Riri to
Zenshu opened by the privately owned
Zenboku Light Railway on 12 November 1917. In 1927, the line was nationalised, Sentetsu then extended the line, completing the Jeonju–
Namwon section in October 1931, In 1936, Sentetsu nationalised the privately owned
Chosen Railway's
Gwangnyeo Line, which ran from
Songjeongni to Yeosu and
Yeosu Port via
Suncheon, renaming it
Songnyeo Line and splitting it apart to merge the Suncheon–Yeosu section with the Jeonbuk Line to create the
Jeolla Line in 1936. Byeongpung Tunnel, north of
Suncheon, and the long Seulchi Tunnel, south of
Jeonju, which became South Korea's longest rail tunnel, The three sections of the first phase with altogether , shortening the original route by , were finished by 1999 and entered service on 18 May 1999. to allow speeds of . By March 2010, progress on the section from Iksan to Suncheon reached 63.0%. with work starting in December 2003. As of March 2010, progress on the long alignment stood at 88.0% out of a total budget of 732.002 billion won. The entire upgrading project is to be completed in 2011. ==Major stations==