 This track is used in non-revenue service to connect the tracks of Line 4 and Line 10.The Hôtel de Cluny was once the town house of the abbots of Cluny and is now the Musée de Cluny, an important museum containing a variety of artifacts from the Middle Ages.The Hôtel de Cluny is partly constructed on impressive remains of Gallo-Roman baths dating from the 3rd century (known as the Thermes de Cluny) and may still be visited.