Milan, evermore in the heart of Europe: east to west in just 30 minutes with the new M4 Milan line

The M4 or "Blue Line" is the new Milan metro line, an engineering project that is essential for developing the Lombardy capital and strengthening its position in Europe. Milan’s M4 runs under the city from east to west, passing through the historic centre and reaching Linate airport. From its two terminals, Linate and San Cristoforo, the Milan M4 line is 15 km long with 21 stations. Travelling between these two stations it only takes 30 minutes, and only 12 minutes from Linate Airport to the city centre.

The new metro line is entirely underground, fully automated and driverless, allowing for the use of safer and more efficient driverless trains. The M4 crosses Milan's historic centre, allowing rapid travel along the east/west route of the city, significantly reducing road traffic.

In addition to the interchange with Linate airport, the work has two interchange stations with the existing metro line: with the red line at San Babila station and with the green line at Sant'Ambrogio station. The M4 is connected to the suburban railway lines at the Forlanini FS, Dateo and San Cristoforo stations. Thanks to a short pedestrian connection to the outside that starts at Sforza Policlinico station, it is possible to reach the yellow line at Missori station.

The project involved building two single-track tunnels, one for each direction, 21 stations, 30 buildings and a workshop depot. The M4 Metro mainly falls within the perimeter of the Municipality of Milan, running for a small portion into the territory of the municipalities of Segrate and Peschiera Borromeo, near the eastern terminal.

M4 Metro stops

The completion of work on the first section is the first milestone in a long process that began in 2012. After the awarding of the tender and the first surface works, the first excavation at the Linate site dates back to 24 March 2014 and was completed a few months later.  

After the Municipality of Milan approved the project for the central section, the tunnel excavations that cut the city in two also began in 2017.

In September 2020, the excavations of the tunnels of the entire line were completed: 30 km for two tunnel pipes that run without interruption from Linate station to S. Cristoforo, along the east-west route. In 2021, works were completed on the Linate-Forlanini section.

The completion of work on the first Linate-Forlanini section brings the M4 project closer to a number that alone tells how the project will impact Lombardy's capital city. 12 minutes is the time that takes to travel from the Linate airport to San Babila, in the city centre, on board the new "Blue Line" trains.

Linate is one of the metro’s two terminals, the ends of those 15 kilometres of track that, through 21 stations, run along the east-west direction of the city, reaching the other terminal at San Cristoforo. The M4 is the airport's metro line, a strategic infrastructure reducing distances in Milan and also bringing the city closer to the rest of Italy and Europe.

In July 2023 the San Babila Station of the new M4 metro line was inaugurated. Milan’s Linate airport was just 12 minutes away from the city’s historic centre following the inauguration. The Tricolore Station, which precedes San Babila along the line’s route from the airport, was also opened to the public. 

M4 Metro: a premium supply chain that will change Milan's mobility

Construction of the M4 required a supply chain of about 1,300 companies, including suppliers and subcontractors, working to bring Milan closer to Europe in a project that will change Milan's mobility, encouraging the constant participation of the citizens.

Milan's Metro: Some history and a few numbers

The Milan metro network currently consists of five lines (M1, M2, M3, M4 and M5) and a railway link, where 5 suburban lines circulate. In total, there are 118 kilometres. 

The network is managed by ATM (Milan's Transport Company), owned by the Municipality of Milan, in charge of managing transport in Lombardy’s capital and in 51 Municipalities in the Province, serving an area with a total population of 2.4 million citizens.

ATM was founded on 22 May 1931 and in its first thirty years, it invested heavily in road transport development. In 1964, the first metro line in the city was opened: the M1 (the "Red Line") on the Lotto-Sesto Marelli route.

In October 1969, the M2, the "Green Line", was also opened. The M3, the “Yellow Line”, opened in 1990, while the M5, the “Lilac Line”, was opened in 2013 and is the city's first fully automated, driverless line. In 2014, new stations were opened on the M5 (Isola and Garibaldi FS). The line was completed in 2015.