These are used by long-distance trains from throughout Switzerland, and by international trains such as the EuroCity, Cisalpino, InterCityExpress and TGV. Tracks 21 and 22 are underground terminal tracks, served by a single island platform, and located on the southern side of the station. This platform is known as Zürich HB SZU and is used by SZU S-Bahn trains, heading west and south towards Uetliberg and the Sihl valley.