The S3 is a regional railway service of the Zürich S-Bahn on the Zürcher Verkehrsverbund (ZVV), Zürich transportation network, and is one of the network's services connecting the cantons of Zürich and Aargau.
The core of the service links Wetzikon, in the east of the canton of Zürich, and Dietikon, to the west of Zürich. This core service runs via the Hinwil–Effretikon line, joining the Winterthur–Zürich line at Effretikon. It then runs via the Zürichberg Tunnel and stopping at Zürich Stadelhofen and Zurich Hauptbahnhof, before joining the Zürich–Olten line as far as Dietikon.
At the western end of the service, alternate trains are extended further along the Zürich to Olten line, from Dietikon to Aarau, in the canton of Aargau.
The following stations are served:
The ZVV (German abbreviation for Zürcher Verkehrsverbund, translated into English as Zürich Transport Network or Zürich Traffic Network) is a public transportation fare network system, combining virtually all kind of public transport means (rail, bus, tram, trolleybus, lake boat and cable car and the like) and services in the canton of Zürich (including Rapperswil-Jona and Pfäffikon SZ and some other spots), and integrating them into one single fare network and coordinated timetables. The fares are not based on particular lines and connections from A to B, but on the number of zones ones travels through for a specified period of time.
Established in May 1990, the ZVV was initially an elaborate web of railway lines. They were prefixed with the letter S (S-Bahn). S-Lines 1 through 43 (with some lines missing) now form part of the S-Bahn Network. A proof-of-payment fare system is in force on all S-Bahn trains; there are no fare gates, but those without a valid ticket face a minimum fine of CHF 100.