Its 25 kilometre-long, standard gauge line from Wil via Wattwil to Ebnat-Kappel was opened on 24 June 1870.
An option that would have run from Lütisburg to Uzwil or Flawil was rejected for topographical and financial reasons.
A detailed financial estimate amounting to Swiss francs (CHF) 6 million was compiled at the end of 1858.
The operation of the TB was carried out by the United Swiss Railways (Vereinigte Schweizerbahnen, VSB) until its nationalisation.
This virtually free transfer of the TB to the Federal Government was the financial contribution of the canton of St. Gallen to the construction of the CHF 12 million Ricken Tunnel.
In addition, there was a false double track between the two stations, as the lines of the SBB and the BT were laid next to each other.
Electrical operations on the St. Gallen–Wattwil–Nesslau-Neu St. Johann line commenced on 4 October 1931, which also meant that through trains could through the Ricken Tunnel.
With the permanent lease of the Wattwil–Ebnat-Kappel section to the BT, the SBB retired from the operation of Ebnat-Kappel station at the same time.
Steam traction lasted for twelve years on the remaining 20 km of the Toggenburg railway between Wil and Wattwil before electrical operations also started there on 12 December 1943.
An outer platform was built with a pedestrian underpass in Bütschwil, where the half-hourly trains cross.
[2] Since the commencement of the 2013 timetable, Thurbo trains have run on the Wil–Wattwil section as line S9 of the St. Gallen S-Bahn at half-hour intervals.
Services on the line from Wil to Nesslau-Neu St. Johann are set out in the Swiss timetable as table 853.