The S1 is a railway service of the St. Gallen S-Bahn that provides half-hourly service between Schaffhausen and Wil, via St. Gallen, in the Swiss cantons of Zürich, Thurgau, Schaffhausen, and St. Gallen. The entire line is also part of the Bodensee S-Bahn.[4] THURBO, a joint venture of Swiss Federal Railways and the canton of Thurgau, operates the service.