Ludwig South-North Railway

It was named after the king, Ludwig I, whose infrastructure priorities had earlier been focused less on railway development than on his Main-Danube canal project.

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.

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).

Sometimes-conflicting objectives included the avoidance of over-steep sections while nonetheless connecting as many towns and cities as possible with the railway.

After the unification of Germany in 1870, Hof ceased to be a frontier town and the line became a significant component of the national rail network.

Between 1862 and 1892, the opportunity was taken to install a second track, for which space had already been allowed at the time of the original construction: by 1939 electrification had been completed from Nuremberg as far as Bamberg.

The capital was linked in to the national rail network on 1 June 1846 when the Munich–Augsburg railway found itself nationalised in return for a shareholder compensation payment of 4.4 Million Guilders.

Today the south-eastern end of the tunnel, which lies directly beyond the site of the former station, has been converted for warehousing and residential uses.

Between Immenstadt and Lindau the line follows two difficult mountain passes in order to avoid Württemberg, at that time still a foreign state.