The train lines of the Île-de-France Mobilités network serve many stations in the region and have as their departure or terminus the major Parisian stations, or La Défense for the U line. 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!