The Ringbahn (German for Circular Railway) is a 37.5 km (23.3 mi) long railway line of the Berlin S-Bahn network in Germany, around the city centre. The circle route is made up of the double tracked S-Bahn ring and the parallel freight ring. S-Bahn service on the line is provided by lines S 41 (clockwise) and S 42 (anticlockwise), carrying 400,000 passengers a day. Due to its distinctive shape, the line is often referred to as Hundekopf (Dog's Head).