Hamburg U-Bahn Line U4 extension opens; Alstom-Bombardier consortium to supply trains December 13, 2018 | Europe Company News Passenger services have commenced on Hamburg U-Bahn Line U4 extension. The extension spans 1.3 km from HafenCity University to Elbbrücken, covering one station.. The Elbbrücken statio... This content is available to only subscribers. Username or E-mail Password Remember Me Forgot Password