S21 (ZVV)

The S21 is a regional railway service of the Zürich S-Bahn of the Zürcher Verkehrsverbund (ZVV). The service operates at peak hours between Regensdorf-Watt and Zürich Hauptbahnhof over the Wettingen–Effretikon railway, supplementing the regular S6 service, which continues west to Baden. The S21 designation was previously used for service from Zürich to Zug over the Thalwil–Arth-Goldau railway; this is now provided by the S24.

S21 (ZVV)

The S21 is a regional railway service of the Zürich S-Bahn of the Zürcher Verkehrsverbund (ZVV). The service operates at peak hours between Regensdorf-Watt and Zürich Hauptbahnhof over the Wettingen–Effretikon railway, supplementing the regular S6 service, which continues west to Baden. The S21 designation was previously used for service from Zürich to Zug over the Thalwil–Arth-Goldau railway; this is now provided by the S24.