The Ludwig South-North railway (Ludwig-Süd-Nord-Bahn), built between 1843 and 1854, was the first railway line to be constructed by Royal Bavarian State Railways. It was named after the king, Ludwig I, whose infrastructure priorities had earlier been focused less on railway development than on Main-Danube canal project.
The railway ran from Lindau on Lake Constance via Kempten, Augsburg, Nuremberg and Bamberg to Hof where it linked up with the Saxon-Bavarian Railway Company.
Following the successful experiment involving the construction of a railway connecting Munich to Augsburg, which had opened on 4 October 1840, committees sprang up in many parts of Bavaria to plan private railways. The government determined that the building of further railways should become a state responsibility, however. On 14 January 1841 Bavaria concluded with Saxony and Saxe-Altenburg an agreement to build a railway connecting Leipzig with Nuremberg, which would cross into Bavaria at Hof. The parties committed to have the railway ready for operation within six years.
The Bavarian government decided to extend the railway past Augsburg (already connected by rail to Munich, the capital city) through the Allgäu as far as Lake Constance. The necessary legislation was passed in Munich on 25 August 1843. With a budgeted cost of 51.5 million Guilders, it was planned that the entire length would be ready within ten years. The section between Augsburg and Hof would account for 33 million guilders. Space for two tracks would be prepared, but initially only a single track would be laid. Responsibility for the construction would be given to Chief Engineer, August Pauli and, initially, the French-born railroad pioneer Paul Camille von Denis, though Denis had been taken off the project in 1842 in order to take over the construction of a line connecting Ludwigshafen (at the time also ruled by Bavaria) with Saarbrücken (subsequently named the Palatine Ludwig Railway (Pfälzische Ludwigsbahn).