Originally the line commenced outside the main station in Nyon and after passing below the Swiss Federal Railways main line it climbed steadily, steeply in places taking large curves to ease the gradient, to the mountain resort of St. Cergue. From here it runs alongside the road through the Col de la Givrine, with a summit of . above sea level, to the village of La Cure, nowadays its upper terminus. It was here the line crossed the French border and again running alongside the road, passing the village of Les Rousses it duly arrived in the streets of Morez. The line then descended steeply to terminate in front of the PLM station.