At an early stage, it also became apparent that, for synergy reasons, it would make sense to link the Stadtbahn construction with two other major urban projects in the second half of the 19th century. One of these was the Vienna River canalisation, partly underground, and the other was the further extension of the Danube Canal. Both measures were mainly designed for flood protection, with the Danube Canal in the Freudenau also creating a trading and winter harbor, which was also flood-proof. In addition, the Danube Canal also received two collection channels, the left main collecting channel and the right main collecting channel, built in parallel with the Stadtbahn construction in the course of improving canalization in Vienna. The area gained by the straightening of the two rivers could thus be used for the urban railway lines, avoiding the expensive purchase of private land and the demolition of existing buildings.