In addition to the U-Bahn system of Siemens, which was eventually built, the idea of a monorail, as had already been built for example in Wuppertal, was also proposed.
Neben dem später erbauten U-Bahn-System von Siemens gab es auch die Idee einer Schwebebahn, wie sie zum Beispiel bereits in Wuppertal errichtet worden war.