History of the Ruhr and steel industries have declined drastically History of the Ruhr The actual boundaries of the Ruhr vary slightly depending on the source, but a good working definition is to define the Lippe and Ruhr as its northern and southern boundaries respectively, the Rhine as its western boundary, and the town of Hamm as the eastern limit. In the Middle Ages, local power was vested primarily in the counts ("Grafen") of Berg, Mark and Cleves. The left bank of the Rhine was held by the Archbishop of Cologne. The Hellweg was an important trade route crossing the region from Duisburg to
S-train tunnel under the central station and the city centre. The high number of large cities in the Ruhr area promotes a polycentric network connecting all cities and suburbs. The "S-Bahn Rhein-Ruhr", as it is called, features few tunnels, and its routes are longer than those of other networks. The Ruhr S-Bahn is the only S-Bahn network to be run by more than one corporation in Germany, and the Salzburg S-Bahn holds a similar distinction in Austria. Most Swiss S-Bahn systems are multi-corporation networks, however. Most German S-Bahn networks have a unique ticket system, separated from the "Deutsche Bahn" rates, instead