An overview of the planned route for underground line U5 in Hamburg (Germany), with a discussion of advantages and drawbacks. As of 2023, the plans for the first section of the line (between Bramfeld and City Nord) are approved and construction has started. Currently plans are made for the entire route. It is already clear where all stations will be but planning now includes design of the stations with all entrances, there still changes are possible. From U5 you will be able to change to various other rapid transit lines: at Sengelmannstraße to U1, at Borgweg to U3, at Hauptbahnhof and at Jungfernstieg to many other underground and suburban train lines, at Stephansplatz to U1, at Hoheluftbrücke to U3, at Hagenbecks Tierpark to U2 and at Stellingen to suburban trains (as of 2023: S21 and S3 – the suburban network of Hamburg will, however, be re-ordered soon). U5 shall be operated completely in automatic mode. Trains will have no drivers. Most of the line will run through tunnels. Only at Sengelmannstraße station trains will run above ground for a short section. Tunnels will be deep below ground. In the quarters of Winterhude and Uhlenhorst U5 will take some strain of the bus line 6, which has very high passenger numbers. In the west of Hamburg, between central station and Siemersplatz, U5 will run partly parallel to bus line 5. This is one of the most frequented bus lines in Europe. As the stations will lie rather deep under the surface, long ways to and from the platforms will result – and long ways when changing to other rapid transit lines. About 90,000 passengers per day are expected using the U5 stop at Hamburg central station. This means that central station will be even more crowded than it is now. Hamburg still has no rapid tangential or circular lines of public transport connecting the outer quarters. U5 will be no solution for this problem. You could travel from Winterhude to Lokstedt or to Stellingen using U5. But the line passes through the city center in a long arc. This results in long times for the journey. U5 will be a line frequented by many passengers. Should a problem occur, resulting in a temporary shutdown of the whole line or part of it, many replacement buses would be needed.