Gauge
The line from Noyelles sur Mer to Le Crotoy is metre gauge.
The line from Noyelles sur Mer to St. Valery Ville is of dual gauge, with metre gauge tracks laid within standard gauge track, thus having four rails. At St. Valery there is a branch to St. Valery Quai which is dual gauge, but having three rails only. The line from St. Valery Ville to Cayeux (Brighton Plage) is metre gauge.
Read more about this topic: Chemin De Fer De La Baie De Somme