The Ruhr metropolis is a large region that is home to a collection of cities towns and municipalities; interconnected yet not necessarily united as one. Public transport is often divided by administrative boundaries, yet united through a regional association, the Verkehrsverbund Rhine-Ruhr (VRR). This enables travel on one ticket over large distances with one effect; efficient travel from A to B.
While local networks of widespread and popular trams running both overground and underground are highly reliable, the regional service of the Deutsche Bahn often suffers delays to the displeasure of commuters. On the whole a good service; clean and safe but take care to leave enough times for interchanges and walks between systems than can sometimes be a little lengthy.