Südostbahn

and that previously owned by the original SOB located predominantly in Central Switzerland:

Rapperswil–Pfäffikon SZ line,

Pfäffikon SZ–Freienbach SOB–Wollerau–Samstagern–Schindellegi-Feusisberg–Biberbrugg–Altmatt–Rothenthurm–Biberegg–Sattel-Aegeri–Steinerberg–Arth-Goldau line, and

Einsiedeln–Biberbrugg–Schindellegi-Feusisberg–Samstagern–Wädenswil line.

Since 2006, SOB also owns Wattwil station and the railway from Wattwil to Ebnat-Kappel, which until then belonged to SBB CFF FFS. The railway stations of Romanshorn, St. Gallen, and Pfäffikon SZ, and the railway tracks between St. Gallen St. Fiden–St. Gallen, Wattwil (except railway station)–Rapperswil, and Arth-Goldau–Luzern are owned by Swiss Federal Railways, but are used by SOB for its services.

In total, the SOB network measures 128.9 kilometres (80.1 miles), and comprises the following lines:

Romanshorn – St. Gallen St. Fiden (19.1 kilometres (11.9 miles))

St. Gallen – Wattwil – Nesslau-Neu St. Johann (44.5 kilometres (27.7 miles))

Rapperswil – Pfäffikon SZ (Seedamm) (4 kilometres (2.5 miles))

Pfäffikon SZ – Arth-Goldau (34.6 kilometres (21.5 miles), including 6.1 kilometres (3.8 miles) common with Wädenswil–Einsiedeln)

Wädenswil – Einsiedeln (16.7 kilometres (10.4 miles))

The adhesion railway network spreads over mountainous terrain, with a maximum slope of 50‰ (5 %) between Wädenswil/Pfäffikon SZ and Biberbrugg, and between Rothenthurm and Arth-Goldau. The lowest altitude on the SOB network is found at Romanshorn (399 metres (1,309 ft) a.s.l.), and the highest at Biberegg (933 metres (3,061 ft) a.s.l.), between Rothenthurm and Sattel-Aegeri. The highest elevation on the section between Nesslau-Neu St. Johann and St. Gallen is reached near Degersheim (798.7 metres (2,620 ft) a.s.l.).

The network is mostly a single-track railway, with intermittent double-tracks (9.84 kilometres (6.11 mi) in total) present in sections where trains cross regularly. The entire network is electrified since 1939.

Services

InterRegio

Südostbahn (SOB) operates InterRegio (IR) services as named trains Voralpen-Express, Treno Gottardo, and Aare Linth. Due to the clock-face scheduling, the Swiss rail network offers passengers timely connections at most railway stations. Since 2018, most InterRegio lines in Switzerland are numbered and color-coded for more clarity.

Voralpen-Express

From 1992 to 2013, Voralpen-Express (English: "Prealps Express") was jointly operated with the Swiss Federal Railways (SBB CFF FFS), and it continued as a regional train between St. Gallen and Romanshorn. It is since operated solely by SOB, and the trains turn around in St. Gallen. Between 2013 and 2019, Voralpen-Express ran under its own train category (VAE). It is now again classified as InterRegio (unnumbered) after it was briefly categorized as Panorama Express (PE). The name Voralpen-Express is still indicated on platform displays and mentioned during train departure announcements at the platform.

IR Voralpen-Express: Luzern – St. Gallen

Luzern – Luzern Verkehrshaus – Meggen Zentrum – Küssnacht am Rigi – Arth-Goldau – Rothenthurm – Biberbrugg – Pfäffikon SZ – Rapperswil – Uznach – Wattwil – Herisau – St. Gallen

Voralpen-Express runs mainly on tracks of the SOB network but uses tracks owned by Swiss Federal Railways between Lucerne and Arth-Goldau, and between Rapperswil and Wattwil (including the 8.6 kilometres (5.3 mi) long Ricken Tunnel on the Uznach–Wattwil line).

Treno Gottardo

Treno Gottardo (Italian for "Gotthard train") is jointly operated by SOB and SBB CFF FFS and runs entirely on the network owned by the latter. It connects the city of Locarno, in the Italian speaking part of Switzerland, alternately with the cities of Basel and Zurich, both located in the German speaking part of the country. Trains to/from Basel reverse direction at Lucerne (dead-end station). It was launched in December 2020, but trains turned around at Bellinzona until spring 2021 due to construction work between Bellinzona and Locarno at that time.

Basel SBB – Locarno

Basel SBB – Olten – Luzern – Arth-Goldau – Schwyz – Brunnen – Flüelen – Erstfeld – Göschenen – Airolo – Ambri-Piotta – Faido – Lavorgo – Bodio TI – Biasca – Castione-Arbedo – Bellinzona – Cadenazzo – Tenero – Locarno

Zürich HB – Locarno

Zürich HB – Zug – Arth-Goldau – Schwyz – Brunnen – Flüelen – Erstfeld – Göschenen – Airolo – Ambri-Piotta – Faido – Lavorgo – Bodio TI – Biasca – Castione-Arbedo – Bellinzona – Cadenazzo – Tenero – Locarno

Treno Gottardo follows the scenic route of the Gotthard Railway. This "old route" crosses the Alps through the ca. 15 kilometres (9.3 mi) long Gotthard Tunnel between Göschenen (1,106 metres (3,629 ft) a.s.l.) and Airolo (1,142 metres (3,747 ft) a.s.l.). It uses a series of spiral loops and horseshoe curves (partly in tunnels) to quickly gain altitude, or to lose altitude on the other side of the tunnel, respectively. All InterCity and EuroCity trains instead use the 57.09 kilometres (35.47 mi) long Gotthard Base Tunnel since its opening in 2016.

Aare Linth

The named train Aare Linth was launched in December 2021. It connects Chur, the capital of Canton Grisons, with the Swiss capital of Bern. The trains reverse direction at Zurich mainstation (Zürich HB), which is a cul-de-sac. The train is named after the Aare and Linth rivers, which it follows/crosses on its journey. Aare Linth is operated by SOB in cooperation with SBB CFF FFS; it runs entirely on the Swiss Federal Railways network. Stadler "Traverso" trainsets operate on this InterRegio line except during rush hour, when higher-capacity rolling stock of SBB CFF FFS is used.

Bern – Chur

Bern – Burgdorf – Herzogenbuchsee – Langenthal – Olten – Zürich Altstetten – Zürich HB – Thalwil – Wädenswil – Pfäffikon SZ – Siebnen-Wangen – Ziegelbrücke – Unterterzen – Walenstadt – Sargans – Bad Ragaz – Maienfeld – Landquart – Chur

Alpenrhein-Express

In December 2024, the new named train Alpenrhein-Express began operations using Stadler "Traverso" EMUs. It connects Chur with St. Gallen. The train is named after the Alpine Rhine (Alpenrhein), a portion of the Rhine. The Alpenrhein-Express runs mainly over the Chur–Rorschach railway line of Swiss Federal Railways, which follows the Alpine Rhine. This line was upgraded to dual tracks prior to the opening of the service, allowing for a half-hourly InterRegio service. The Alpenrhein-Express operates hourly, while another IR13 service of Swiss Federal Railways operates in between. The latter run between Sargans via St.Gallen to Zurich. The same trainsets used for the Alpenrhein-Express continue as S81 service of St. Gallen S-Bahn (see below), providing hourly direct services between Chur and Appenzell Ausserrhoden's capital Herisau.

St. Gallen – Chur

St. Gallen – Rorschach – St. Margrethen – Heerbrugg – Altstätten SG – Buchs SG – Sargans – Bad Ragaz – Maienfeld – Landquart – Chur

S-Bahn

As of the December 2023 timetable change, Südostbahn (SOB) operates the following S-Bahn services in Central and Eastern Switzerland:

Lucerne S-Bahn:

S31 Arth-Goldau – Steinerberg – Sattel – Biberegg – Rothenthurm – Altmatt – Biberbrugg

St. Gallen S-Bahn:

S4 Rapperswil – Uznach – Kaltbrunn – Wattwil – Lichtensteig – Brunnadern-Neckertal – Mogelsberg – Degersheim – Schachen (Herisau) – Herisau – St. Gallen Haggen – St. Gallen – St. Gallen St. Fiden – Mörschwil – Goldach – Rorschach Stadt – Rorschach – Staad – Rheineck – St. Margrethen – Au SG – Heerbrugg – Rebstein-Marbach – Altstätten SG – Oberriet – Rüthi SG – Salez-Sennwald – Buchs SG – Sevelen – Sargans

S6 Rapperswil – Blumenau – Schmerikon – Uznach – Benken – Schänis – Ziegelbrücke – Nieder- und Oberurnen – Näfels-Mollis – Netstal – Glarus – Ennenda – Mitlödi – Schwanden ( – Nidfurn-Haslen – Leuggelbach – Luchsingen-Hätzingen – Diesbach-Betschwanden – Rüti GL – Linthal Braunwaldbahn – Linthal, only during off-peak hours)

S17 Sargans – Mels – Flums – Walenstadt – Unterterzen – Murg – Mühlehorn – Ziegelbrücke – Schänis – Benken – Uznach – Schmerikon – Blumenau – Rapperswil

S81 St. Gallen – St. Gallen Haggen – Herisau

Zürich S-Bahn:

S13 Einsiedeln – Biberbrugg – Schindellegi-Feusisberg – Samstagern – Grüenfeld – Burghalden – Wädenswil

S40 Einsiedeln – Biberbrugg – Schindellegi-Feusisberg – Samstagern – Riedmatt – Wollerau – Wilen bei Wollerau – Freienbach SOB – Pfäffikon SZ – Hurden – Rapperswil

Not formally part of an S-Bahn network:

S27 (March shuttle) Ziegelbrücke – Bilten – Reichenburg – Schübelbach-Buttikon – Siebnen-Wangen (operates only Monday–Friday during peak-hours)