They seem to have missed one key detail in the title: this is the last European passenger train that travels by sea - or rather, the last ferry crossing that carries passenger carriages (I doubt that they carry the engine across by ferry?). There are (AFAIK) several other ferry lines that carry freight carriages, among them the Rostock-Trelleborg line served by https://en.wikipedia.org/wiki/MS_Sk%C3%A5ne