services stations in the cantons of Aargau, Lucerne and Bern. The RER Fribourg is an S-Bahn-style service centered at Fribourg/Freiburg and Bulle in the Canton of Fribourg, and extending into the cantons of Neuchâtel and Vaud. Two unnumbered S-Bahn services (designated only with an "S"), one between Schaffhausen and Erzingen (D), running on railway tracks owned by Deutsche Bahn (DB), and one between Schaffhausen and Jestetten (D), opened in 2013. They are operated by SBB GmbH and THURBO, respectively. Since December 2022, the Schaffhausen–Singen am Hohentwiel line is also serviced by SBB GmbH (). Additionally, there are services designated "S" that are not part of any formal S-Bahn network. These include the S20, S21, and S22 operated by Swiss Federal Railways in Solothurn or the S27 operated by Südostbahn (SOB) between Siebnen-Wangen and Ziegelbrücke. Swiss S-Bahn services are operated mostly by the Swiss Federal Railways (SBB CFF FFS) but also by private railway companies, such as Appenzeller Bahnen (AB), BLS AG, Forchbahn (FB), Regionalverkehr Bern-Solothurn (RBS), Rhätische Bahn (RhB), Sihltal Zürich Uetliberg Bahn (SZU), Südostbahn (SOB) or Zentralbahn (ZB). Rail transport in Switzerland, including S-Bahn systems, is noteworthy for its coordination between services due to the clock-face schedule. Due to the proximity of the various S-Bahn systems in Switzerland, services of one network often offer connections to services of neighboring networks. S-Bahn services are used by commuters and tourists (some services call nearby tourist attractions, such as the Rhine Falls or the Swiss Museum of Transport). See also Commuter rail U-Bahn Urban rail transit Train categories in Europe List of suburban and commuter rail systems References External links