Complex sentence: In December 1858 the Hessische Ludwigsbahn opened the line to Aschaffenburg via the then state capital of Darmstadt, but, as no bridge had been built over the Rhine, it ended on the right Rhine bank above the Main delta.
Split into simpler sentences: In December 1858 the Hessische Ludwigsbahn took after to line Aschaffenburg via the then state capital of Darmstadt in service. In the absence of a bridge this however ended on the right Rhine bank above the Main delta.