Bremen has ten tram routes, totaling 84 route kilometers, including 78 modern low-floor trams, and 61 older vehicles. Most of the system is street running, but several there are several recent upgrades to light rail, with many more near completion or in design. Several seperate right of ways also exist from an unfinihsed metro project in the 1970's. The system is entirely above ground.
The first line (with horses) opened June 4, 1876. The first electric line operated in June 1890, It was the first line in Europe to have a tram system. Bremen is also the first city with 100% low-floor streetcars, it has now 78 of them plus 61 old ones from the 70's. It's unfortunate, that you cannot run these kind of trams because of the strict American laws.
The first of several planned links between the tramway and heavy rail lines opened in 2004. A new 500m chord linking the light and heavy rail systems at Neustadt will allow for a potential new regional rail service linking Bremen with Delmenhorst and Nordenham, over 80km away.
Andreas was kind enough to email me a few photos and stats on the Bremen streetcar.LRT system.
Bremer Straßenbahn AG
Low floor tram 3024 at the major transfer station, Domscheide.