The two sections Offenburg–Hausach and Engen–Singen were opened for service in 1866, and the other parts of the line were finished in the next several years. Due to the further delays caused by the Franco-Prussian War in 1870, the Black Forest Railway was not completed in its entirety until 10 November 1873. In addition, the section Singen–Konstanz, which had been opened in 1863 as part of the Baden Mainline, was operationally linked to the Black Forest Railway. Plans were also drawn up to connect the Elz Valley Railway from Freiburg via Elzach with Hausach, but this was never realized.