The SBB network covers Switzerland at national scale, with dense links between the German-, French-, and Italian-speaking regions. Main corridors include Zurich-Bern-Lausanne-Geneva, Basel-Zurich, Basel-Bern, Zurich-Lucerne, and the north-south Gotthard axis via Arth-Goldau, Bellinzona, and Lugano. Major hub stations include Zurich HB, Bern, Basel SBB, Geneva Cornavin, Lausanne, Lucerne, St. Gallen, and Lugano. SBB operates InterCity and InterRegio trains on long-distance corridors, RegioExpress and regional trains on shorter routes, and S-Bahn networks around cities such as Zurich, Basel, Bern, and Vaud. Service frequency, stopping pattern, and reservation options vary by route and train category.