Metro M4, Milan
The new M4 line in Milan is an infrastructure that will provide a fast link between the East and South-West areas of the city.
It will cover a distance of more than 15 km between Linate airport and central Milan, with 21 stations, 29 service facilities and a warehouse/depository. The fleet will be made up of 47 vehicles, seven of which will be reserve vehicles, with four intercommunicating boxes for a total length of 50.50 m with a maximum capacity of 600 passengers per train, with a minimum design frequency of 75 seconds; the line, therefore, will have a maximum transport capacity of 24,000 passengers per hour and per direction. Most of the underground development of the route (about 13.000 m of single-track tunnel per direction) is excavated mechanically using six TBMs (Tunnel Boring Machines), two used in the Central section (Tricolore-solari Park station) with an excavation diameter of 9.15 m, two with a smaller excavation diameter of 6.36 m, used in the eastern external section (Line-Tricolore station) and finally two with an excavation diameter of 6.70 m, used in the western external section (Parco Solari-San Cristoforo FS station).