The retreat of the South went chaotically and slowly, the army was surrounded in the area of Pontarlier, close to the Swiss border.
In France, the intended connecting line was completed as far as Pontarlier near Vallorbe in 1875.
To achieve this, it founded in 1856 with other investors the Franco–Swiss Company, and subscribed 40% of the capital for the construction of a railway line from Pontarlier in France to the Swiss border at Les Verrières through the Val-de-Travers to Neuchâtel.