Overhead railway installation between the Kreuzberg district boundary and Nollendorfplatz including entry ramp, 1899-1902 by Heinrich Schwieger, Alfred Grenander, Bruno Möhring, Cremer & Wolffenstein
Oberbaumbrücke 1892-96 by Otto Stahn
The standard railway system built by Siemens & Halske in 1896 and 1902 (presently line U1/U2) was Germany's first electrical overhead and underground railway system and is considered to be a master achievement in technical engineering. Linked to transfer stations of the city commuter railway, the rail line from East Berlin through the southern belt was built during the period of imperial consolidation via the Potsdam and Anhalter railway terrain to Charlottenburg. The Hochbahnviadukt (elevated train viaduct) and overhead railway stations were planned by Heinrich Schwieger and Johannes Bousset as transparent constructions of iron framework and austere engineering, and its easterly section was executed accordingly. The western stretch of the viaduct route and its railway stations, however, were built in a considerably more stately design. In accordance with a planning change in 1899, the line beginning at Nollendorfplatz station was constructed as an underground railway. Alfred Grenander developed design principles for underground stations of the standard railway which remained obligatory for Berlin's U-Bahn constructions for many decades.
In addition to station types (Warschauerstrasse, Görlitzer Bahnhof and Prinzenstrasse), the present standard railway is characterized to a great extent by Bruno Möhring's "artistically detailed" overhead railway stations at Bülowstrasse, Kottbusser Tor and Hallesches Tor, the latter of which were later reconstructed and renovated by Alfred Grenander. The Oberbaumbrücke, constructed from1894-96 according to plans by Otto Stahn, serves as the Spree crossing to the terminal station at Warschauer Strasse. Reconstructed from 1992-95, it symbolizes the integration of the once divided city.