the orbe-chavornay railway (o-c) is a 3.9 km standard gauge railway in vaud, switzerland, linking the towns of orbe and chavornay (where there is an interchange with trains of the swiss federal railways. the line was opened in 1894 and was operated by electric traction from the start - the first electrified standard-gauge railway in switzerland. the line was initially operated with a direct current overhead power supply 600 volts and is now 750 volts.