Südostbahn

The Schweizerische Südostbahn AG (German, lit.'South-Eastern Railway'), commonly abbreviated to SOB, is a Swiss railway company, and a 1,435 mm (4 ft 8+1⁄2 in) standard gauge network in Central and Eastern Switzerland. It resulted from the merger of the original SOB with the Bodensee–Toggenburg railway (BT) at the end of 2001.

The Schweizerische Südostbahn AG (Swiss South-Eastern Railway SA) is a small private railway jointly owned by the cantonal and federal governments as an Aktiengesellschaft (AG).

The Südostbahn is one of the three major standard gauge railway operators im Switzerland, the other two being Swiss Federal Railways and BLS AG.