The Zurich S-Bahn (German: S-Bahn Zürich) system is a network of rail lines that has been incrementally expanded to cover the ZVV area, which comprises the entire canton of Zurich and portions of neighboring cantons (Aargau, Schaffhausen, Schwyz, Thurgau and St. Gallen), with a few lines extending into Germany. The network is one of many commuter rail operations in German speaking countries to be described as an S-Bahn.
The entire ZVV S-Bahn network went into operation in May 1990, although many of the lines were already in operation.
The lines of the S-Bahn network are numbered from S2 to S55, but the numbering is rather sporadic, with several missing numbers (e.g. S19, S20).
Unusual among rapid transit services, the Zürich S-Bahn provides first class commuter travel; about one-fifth of seats on each train are first class.