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 neighbouring cantons (Aargau, Glarus, Schaffhausen, Schwyz, St. Gallen, Thurgau and Zug), with a few lines extending into or crossing the territory of southern Germany.

It was connected to lines to the north and northeast via the Wipkingen Tunnel and Zürich Oerlikon railway station.

This development came about because, after World War II, there was a rapid expansion of commuting to Zurich from the former wine-growing villages along the railway line, which originally opened in 1894.

Development of the line would only serve local interests and would not lead to increased revenue for Swiss Federal Railways (SFR).

At the time the canton and cities affected could not fund improvements to an SFR line, so the law was changed to allow local contributions.

[5] The new Gold Coast Express service operated a regular schedule every half-hour, with the total journey time for the distance of 36 kilometres (22 miles) reduced from the previous 60 to 40 minutes.

The most striking feature of the improved railway was the three-car claret-coloured RABDe 12/12 electric multiple units.

The modern features of the Mirages included automatically closing doors, which allowed short stops at stations and a reduction in travel time.

The first would have allocated CHF 200,000 for a study on the construction of a two-line U-bahn (underground railway) with lines from Enge to Kloten and from Altstetten to Tiefenbrunnen; but it was opposed by the majority of the City Council and failed.

The city had already considered such a proposal and opposed it, on the basis that Zurich was not big enough for an underground railway, and it would cost too much.

[7] Following further work and the enactment of a new transport act, the regional public transport authorities presented a new proposal for a combined regional U-Bahn and S-Bahn system, with the latter being a railway network centred on a tunnel under the city centre, which would connect to existing suburban railway lines.

From Zurich Airport, an U-Bahn line would run via Glattbrugg, Oerlikon, Hirschenwiesen, Central, Zürich Hauptbahnhof, Stauffacher and Altstetten to Dietikon.

[10] At a referendum on 29 November 1981, Zurich's voters approved by a two-thirds majority a loan of CHF 520 million for the construction of the core of the S-Bahn.

In several stages, S-Bahn services were expanded to a 380 kilometres (236 miles) rail network, and peak hour express trains were added.

The first stage of the expansion addressed the chronic overcrowding of trains on the S12 route between Dietikon and Zurich, requiring improvements in the Limmat valley.

The widening of the railway to four tracks between Dietikon and Killwangen allowed the separation of the S-Bahn from the long-distance and freight services.

On 12 December 2004 (coinciding with the completion of the first stage of Rail 2000), the S3 service was extended from Dietikon through the Heitersberg Tunnel to Aarau with a new station at Mellingen.

On the rural feeder lines around Winterthur (S33 to Schaffhausen, S35 to Wil and S41 to Bülach) services were increased to run every half hour.

Following a successful referendum, a project was established to create a new route between the Hauptbahnhof and Oerlikon station.

Further improvements in the corridor between the airport and Winterthur are being developed as part of the second stage of Rail 2000 for long-distance trains, which would require further adjustments for the S-Bahn.

[18] In September 2014 a study was published for the construction of a new rail tunnel and underground station serving the ETH Hönggerberg "Science City".