The train lines of the Île-de-France Mobilités network serve many stations in the region and depart from or terminate at the major Parisian stations, or La Défense for line U. Operated by the SNCF, they even venture outside the region for a few stops on lines J, H and R. Inherited from existing lines, It was in the first half of the 2000s that they acquired their current names. These trains are essential for the mobility of Ile-de-France residents and this network is very dynamic: every day, there are as many trains running in Île-de-France as TER trains throughout France!