Hannover is the capital of the German federal State Lower Saxony. Here the tram system has been developed into a light rail system. In the inner city area the trains are running in tunnels, in the outer quarters the lines are built on street level. Such a system is cost efficient and it combines advantages of a tram and of an underground system. All vehicles in Hannover are high-floor vehicles. All tunnel stations have high platforms, as well as most of the stops on street level.
In the video you can see 3 types of vehicles: the green TW 6000, the green and silver TW 3000 and finally, in the street scenes at central station, the TW 2500, kept mainly in silver. They only a drivers' cab at one end and so they are used as couples.