[2] The Paris–Mulhouse railway leaves the Gare de l'Est in Paris in eastern direction.

It enters the Aube valley near Jessains, and continues upstream along Bar-sur-Aube.

It leaves the Aube and enters the upper Marne valley at Chaumont.

It passes Langres and the railway junction Culmont-Chalindrey, where it crosses the line Nancy–Dijon.

The sections between Nogent-sur-Marne and Flamboin-Gouaix, between Troyes and Langres, and between Dannemarie and Mulhouse were opened in 1857.