Public transport in Berlin can be quite confusing, as there are sections of the underground, which run as an elevated railway, while some suburban surface trains run undergrund in the city center. In real life, this is not so important as all modes of transport have a common tariff system, and tickets bought at the suburban surface train are also valid for the underground, trams, and buses, and vice versa.
The Oberbaumbrücke was opened in 1895.
German troops blasted the central section at the end of world war two in an absurd attempt to stop the Russians from crossing the river Spree.
After the war, the entire bridge belonged to the Russian sector. The middle section was soon replaced and underground trains, motorized vehicles, and pedestrians were crossing the bridge.
In 1948, the first deadly incident at the inner-german border happened here: A West Berlin smuggler killed an East Berlin policeman by knocking him down with van. While the East German authorities blamed Western antisocialist intelligence agencies sending a provocateur to commit an act of terrorism, police investigations were unable to confirm such a motif.
In 1955, East German authorities closed the bridge for motorized traffic and the underground, and in 1961 for pedestrians. In the following years, the bridge was opened for pedestrians during short periods of time, until it became a regular checkpoint for Western pedestrians in 1972.
Because the entire river Spree was East German territory, several children died who fell into the river during playing and drowned. West German rescue forces were not allowed into the water, and East German border troops did not care for the life of West German children. In 1976, an agreement between both German states was settled and an SOS telephone was installed at the western end of the bridge. West Berlin rescue forces had to push a button, upon which the East German border officials gave the permission to enter the water and rescue the person.
After the German reunification, the bridge was thoroughly renovated and a new central section was inserted. Tram tracks were installed for a possible future use. The bridge reopened in 1995, first with the sidewalk underneath the underground bridge with its gothic-style arcades.
Notice the Prussian eagle and the Berlin bear on top of the bridge towers.