The line was renamed the Electoral Frederick William Northern Railway (
Kurfürst-Friedrich-Wilhelms-Nordbahn) in 1853 and after the annexation of Hesse-Kassel by Prussia as a result of the
Austro-Prussian War in 1866 it was renamed Hessian Northern Railway (
Hessische Nordbahn). The name Frederick William Northern Railway is not only applied to the line between Kassel and Bebra, but also to the whole route between Warburg and Gerstungen. The first line built in the Electorate was the
Carl Railway, the line between Kassel and the
Weser river port of Carlshafen (now
Bad Karlshafen) then considered the most important line to be built in the state. Subsequently, the two links to Warburg and Gerstungen were added to create the Frederick William Northern Railway. It soon became apparent, however, that the expected traffic to Carlshafen would not eventuate, as traffic quickly moved from the Weser to the emerging rail network. The line to Carlshafen soon became a line of only local significance. This meant that the name Carl Railway was applied to the branch from
Hümme to Carlshafen. The name of the Frederick William Northern Railway was transferred to the much longer line between Warburg and Gerstungen. Thus, from the Hessian perspective, the Frederick William Northern Railway was the first stage of a plan to build a rail network in the Electorate. Only the western branch and the
Main-Weser Railway were completed during the existence of Hesse-Kassel. The eastern branch from Bebra to
Fulda and
Hanau (the
Frankfurt–Bebra line),—all Hessian cities and thus of highest priority for the Electorate—crossed difficult topography and therefore was not completed until Hesse-Kassel was annexed by Prussia in 1866. ==Construction ==