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.
The S-Bahn lines S 41 (clockwise) and S 42 (anticlockwise) have the rare service pattern of a full ring, with no terminus.

In addition, the Lines S45, S46 and S47 use a section of the southern and western Ring, while the Lines S8 and S85 use section of the eastern Ring.
The combined number of passengers is about 400,000 passengers a day.
Due to its distinctive shape, the line is often referred to as the Hundekopf (Dog's Head).

The Ring is structured by the east-west railway thoroughfare called the Stadtbahn (city railway), crossing the Ring in the west at Westkreuz and in the east at Ostkreuz (Eastern Crossing) into a Südring (Southern Ring) and a Nordring (Northern Ring), and by the north-south S-Bahn link (with the North-South S-Bahn-tunnel as its central part) crossing at Gesundbrunnen station in the north and both Schöneberg station and Südkreuz in the south into a Westring (Western Ring) and an Ostring (Eastern Ring).
These four sections served as tariff zones of the railway Berlin suburban fare structure before the previous world war.

Today, the Ringbahn is the boundary of the "Berlin A" zone in the Verkehrsverbund Berlin-Brandenburg's fare structure, and the road traffic control zone for the low emissions established on 1 January 2008.
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. The S-Bahn lines S 41 (clockwise) and S 42 (anticlockwise) have the rare service pattern of a full ring, with no terminus. 
In addition, the Lines S45, S46 and S47 use a section of the southern and western Ring, while the Lines S8 and S85 use section of the eastern Ring. The combined number of passengers is about 400,000 passengers a day. Due to its distinctive shape, the line is often referred to as the Hundekopf (Dog's Head).
The Ring is structured by the east-west railway thoroughfare called the Stadtbahn (city railway), crossing the Ring in the west at Westkreuz and in the east at Ostkreuz (Eastern Crossing) into a Südring (Southern Ring) and a Nordring (Northern Ring), and by the north-south S-Bahn link (with the North-South S-Bahn-tunnel as its central part) crossing at Gesundbrunnen station in the north and both Schöneberg station and Südkreuz in the south into a Westring (Western Ring) and an Ostring (Eastern Ring). These four sections served as tariff zones of the railway Berlin suburban fare structure before the previous world war.
Today, the Ringbahn is the boundary of the "Berlin A" zone in the Verkehrsverbund Berlin-Brandenburg's fare structure, and the road traffic control zone for the low emissions established on 1 January 2008.
Berlin Ringbahn