Overview: Nîmes - Alès - Grand Combe - Villefort - Langeac A train journey on the shortest rail link between Paris and Marseille with the Cevénol Express. This line was built in the 19th century along the Allier River by the Massif Central. More than 100 tunnels and viaducts were constructed in this wild and poorly accessible area. This makes this train journey from Nimes to Langeac a good way to discover this part of France.