S-Bahn train in the tunnel under Wien Hauptbahnhof (Vienna Main Station)
The Austrian Federal Railways (ÖBB) had electrified many railway lines at the very early days of mainline electrification choosing the then most-advanced low-frequency alternating current system with 15 kV, 16 (2/3) Hz AC voltage. The federal capital Wien was reached by electric trains in 1952 as the main area for electrification had been the mountain passes. In those years Austria was still under Allied occupation with the capital being inside the zone controlled by the Soviet Union but the city itself split up into four control zones very similarly to those of Berlin. But while Berlin and Germany gradually shifted into an Eastern and Western part Austria was jointly run by the four allies and in 1955 given independence.After that, the development of the city sped up and required the establishment of a commuter railway network which later incorporated various rail links inside the city and became the Vienna S-Bahn. The main vehicle on the S-Bahn became the ÖBB class 4030 electric multiple unit which had almost the same features as the subject of the present article, only being different in exterior design and the electric systems.