HafenCity Hamburg is one of the largest urban development projects in Germany. In the south of Hamburg's city centre, around 155 ha of port area (including water area) are being restructured. On a land area of approx. 100 ha, new buildings with apartments for approx. 12,000 occupants and service areas for over 40,000 jobs are being constructed. As a consequence of the urban development of HafenCity, not only a proper road infrastructure development, but also a sustainable connection to public transportation is required. After thoroughly investigating all eligible transportation systems, the Free and Hanseatic City of Hamburg has decided to develop HafenCity via a new underground rail line (U4). The owner of the U4 underground project is Hamburger Hochbahn AG.

The new underground line (U4) was equipped with flood protection gates. In case of a water ingress, the area of Überseequartier station or even a section of the line can be protected against flooding. As analysed in a preliminary study, swing gates are the most suitable gate types for the intended use in consideration of the structural and functional requirements. In the opened position, the gate is located under the ceiling where it is locked. For closing the flood protection gate, the lock is released and the gate is lowered by means of hydraulic cylinders. Currentless closing is also possible.

Scope of planning:
- Flood protection gates: Width = 5190 mm, height = 4200 mm
- Drive system with hydraulic cylinders and brackets
- Gate locking mechanism, activated by electrical lifting cylinders
- Safety door for escape tunnel:
clear width = 3600 mm, clear height = 2500 mm; weight = 1900 kg
- Safety door lifted (before opening and closing) by spindle hoist element with crank handle