In 1987, the Bodensee-Toggenburg-Bahn (BT) got the 6 locomotives Re 4/4 # 91 to # 96, built by SLM and BBC with 3200 kW and a maximum velocity of 130 km/h. They were later designated Re 456 and with the merger of the BT with the Schweizerische Südostbahn in 2001, they ran for the new Südostbahn, mainly in the Voralpen Express services. Since change of timetable in december 2019, the Voralpen Express changed to the TRAVERSO trainsets and this 6 locomotives became surplus. Now 2 are sold to the SZU and 2 to the DSF (association Depot und Schienenfahrzeuge Koblenz). On january 27th 2021, there was a "goodbye trip" and a parade with all six locomotives in Herisau.