The MF 77 (abbreviated from the French: Metro Fer appel d'offre 1977) is a steel-wheeled variant of the rolling stock used on the Paris Métro. First used in 1978, it now runs on Lines 7, 8, and 13.Unlike previous models, the MF 77 was designed for travel into the immediate suburbs of Paris, and as a result has a maximum speed of 100 km/h (62 mph) which has yet to be fully utilised. In addition, it sports a new, curved silhouette with a wider midsection.