The mining of iron—for which the railway had been built among other things—stagnated and the income from the transport of timber and ice on the short line did not make profitable operations possible.

Although the Pont–Brassus Railway opened a 13.3 kilometre-long extension of the branch line to Le Brassus on 21 August 1899, operating expenses increased significantly more than revenues from 1890.

The lack of fuel led to an intensification of forestry including charcoal burning in the wooded Vallée de Joux.

People visited the villages along the Lac de Joux for summer holidays and in winter for ice skating or tobogganing.

[3] The economic crisis in the 1930s led to a sharp decline in freight and passenger traffic.