U4 (Hamburg U-Bahn)

The U4 is a line of the Hamburg U-Bahn, and the shortest with a length of 11.9 km. It serves 11 stations and the line opened in 2012. From Jungfernstieg to Billstedt, the line connects with the U2 line. The line is under construction one station from HafenCity Universität to Elbbrücken.

Projected extensions
In January 2013 the government of Hamburg decided to build the U4 one more station to Elbbrücken. At Elbbrücken the U4 will have connections to the Hamburg S-Bahn. In April 2015 the construction works for the extension of U4 line started. The opening of the new Elbbrücken U-bahn/S-bahn station is planned for 2018.