Paris's public transport authority Île-de-France-Mobilités (IdFM), together with transport operator RATP, Transilien SNCF Voyageurs, SNCF Réseau, and SNCF Gares & Connexions, has confirmed an investment programme worth nearly EUR 3.8 billion for 2026 to advance the maintenance and modernisation of the railway infrastructure in the Paris metropolitan area. With support from the Île-de-France region and the French government, the programme aims to improve reliability, safety, and comfort on the heavily used RER and metro networks, while simultaneously preparing for the integration of the future Grand Paris Express lines 15, 16, 17, and 18. Key projects include the introduction of the new MF19 metros on eight lines, further modernisation work on the RER C suburban rail line, preparations for the deployment of MI20 electric multiple units (EMU) on the RER B line, and the comprehensive modernisation of the RER D line with the start of operations of the RER NG vehicles and the expansion of maintenance depots. Additional major construction and modernisation projects include the renovation of the heavily used Nation station on the RER A line, track switch replacements on sections of the RER B and D lines, and overhead line and flood protection work on the RER C line, some of which will require significant service disruptions during the summer months.
