Rhein-Ruhr area is one of Europe's major metropolitan areas. It's made up of some 15 big cities (>100,000, including Düsseldorf, Essen, and Dortmund) and many smaller ones and is said to have about 7 million inhabitants. Directly attached to the south is the Rhein-Sieg metropolitan area (including Cologne and Bonn).AmiDelf said:Is this trams going between small towns which are pretty close to each others? Or? Very nice system. Big maps though
Together it's 12 million inhabitants (http://en.wikipedia.org/wiki/Rhine-Ruhr) and can almost be called a German New York City, though much more spread out and with less common identity. It also lacks the skyscrapers and the feel of a real metropolis. It consists of 25 big cities and has 45 universities, 3 airports, 12 S-Bahn lines, and some 20-40 metro tram lines.
It's hard to count the metro tram lines because many of them share tracks. You can find anything from genuine trams to metro tram lines that run partly underground and partly share tracks with road traffic. None of the lines can be called a full metro (except perhaps U35). Among the more interesting lines are U35, U11, U18, U79 and Cologne's line 4 and line 18 which runs from Cologne into the underground stretch of Bonn.
It's a bit silly but the transportation and tariff system is still separated into a northern part (Rhein-Ruhr, or VRR) and a southern part (Cologne/Bonn and vicinity, or VRS).
The clearest map of the northern part is the VRR map below:
blue = metro or metro tram lines
orange = S-Bahn lines
purple and green = RE and RB (heavy-rail regional express lines and regional lines)
The same as PDF: http://efa.vrr.de/vrr/linienplan_schnellverkehr.pdf
And, again, the VRS part as PDF: http://www.kvb-koeln.de/german/fahrplan/download/vrs_ges_1204.pdf