was a small 'private' (i.e. jointly owned by the cantonal and federal governments) railway which operated between Romanshorn on the Bodensee (in English, Lake Constance
) via St. Gallen
, Herisau, Degersheim, Wattwil, and Ebnat-Kappel to Nesslau-Neu St. Johann in northeast Switzerland
, with a journey time around 76 minutes.
At the end of 2001 the BT merged with the Schweizerische Suedostbahn (Swiss South Eastern Railway) to form the 'new' Südostbahn (SOB), which is 119 km long.