The U4 is a line of the Berlin U-Bahn, and the second shortest after the U55 with a length of 2.86 kilometres (1.78 mi). It serves five stations, with only the termini being step-free.
[edit] History
In 1903, the then-independent town of Schöneberg, south-west of Berlin, planned to develop an underground railway line to improve public transportation. As the line promised less profit, the negotiations with the former Berliner Hochbahngesellschaft (English: Berlin Elevated Railway Company) were unsuccessful. Consequently, Schöneberg started to build the line itself on December 8, 1908. Two years later, the construction was finished and, on December 1, 1910, the line was put into operation. Because this line was separate from the pre-existing underground railway, new equipment was required; Schöneberg chose to use tracks and trains compatible with the rest of the fledgeling network, allowing future connections.
Although Schöneberg owned the track, upon opening, it handed operations over to the Hochbahngesellschaft.
