Tolong jelaskan mengenai France dari Lebar sepur ganda

The Chemin de Fer de la Baie de Somme in France is dual gauge between Noyelles-sur-Mer and Saint-Valery-sur-Somme. The line has four rails with metre gauge laid within standard gauge. There are some dual-gauge (standard and Iberian) sidings at Cerbère on the Spanish border.