The Nienburg–Minden railway is a single track branch line in Lower Saxony and North Rhine-Westphalia, which connects Nienburg station on the Wunstorf–Bremen railway with Minden station on the Hamm–Minden railway. The most important traffic of the line is the freight running from the marshalling yard at Hamburg to the Ruhr and on to southern Germany as well as the container traffic from the seaports to the hinterland. It is sometimes called the Natobahn (NATO railway) because of its former military importance.