Milan Completes Historic 15-Kilometre Driverless M4 Blue Metro Line Linking Linate Airport to San Cristoforo

Milan Unlocks 15-Kilometre East-West Subterranean Transit Artery

MILAN, Lombardy — In a momentous milestone for urban mobility and environmental decarbonization in Northern Italy, the Municipality of Milan (Comune di Milano), municipal transport operator Azienda Trasporti Milanesi (ATM), and prime engineering contractor Webuild have officially inaugurated the complete 15-kilometre alignment of Milan Metro Line 4 (M4 'Blue Line'). Spanning 21 newly constructed underground stations from San Cristoforo FS in the southwest to Linate Airport (Linate Aeroporto) in the east, the driverless heavy rail line fundamentally alters transit patterns across Italy's financial capital.

With all 21 stations fully operational, commuters can now travel end-to-end across Milan in just 30 minutes, while passengers arriving at Milan Linate Airport can reach the central historic Piazza San Babila in an astonishing 12 minutes, creating one of the fastest airport-to-city-centre transit links anywhere in Europe.

Next-Generation Driverless Automation and Engineering Innovation

The M4 Blue Line represents the pinnacle of modern automated rail engineering, operating with fully autonomous, driverless electric trainsets built by Hitachi Rail and governed by high-density Communications-Based Train Control (CBTC) signaling. To guarantee total passenger safety and service punctuality, every station is equipped with full-height automated platform screen doors synchronized with train doors, enabling peak headway frequencies as low as 90 seconds and an operational capacity of 24,000 passengers per hour in each direction.

Webuild and engineering consortia excavated twin tunnels beneath Milan’s densely built urban fabric utilizing specialized Earth Pressure Balance Tunnel Boring Machines, carefully navigating beneath centuries-old historical monuments, subterranean aqueducts, and existing railway corridors. Advanced ground freezing and micro-tunneling techniques were employed to preserve the structural integrity of historic landmarks throughout the central archaeological zone.

Strategic Strategic Multi-Modal Interchanges Across Milan's Transit Grid

The completed M4 line delivers seamless network integration by intersecting with Milan's existing rapid transit and suburban rail systems at key strategic interchanges. Passengers can transfer directly to Metro Line 1 (Red Line) at San Babila, Metro Line 2 (Green Line) at Sant'Ambrogio, and Metro Line 3 (Yellow Line) via a dedicated subterranean pedestrian corridor connecting Sforza Policlinico with Missori.

In addition, the line interfaces directly with the regional Trenord suburban railway (Suburban Lines S) at San Cristoforo FS, Dateo, and Forlanini FS, allowing thousands of daily regional commuters from Lombardy to enter Milan’s central core without driving into the congested low-emission Zone C traffic zone.

Slashing 180,000 Car Trips Daily and Reclaiming Green Public Squares

Mayor of Milan Giuseppe Sala and regional transport ministers emphasized that Line 4 is a game-changing environmental investment in the fight against urban air pollution. The fully operational line is projected to eliminate up to 180,000 individual car journeys each day, averting more than 75,000 tonnes of CO2 emissions annually across the metropolitan area.

Furthermore, the subterranean construction unlocked over 240,000 square metres of renewed public surface realm. The project transformed streets formerly congested with automobile traffic into pedestrianized green plazas, tree-lined boulevards, and protected bicycle lanes connecting neighborhood parks. Standing as a world-class model of sustainable, integrated public transit, Milan’s M4 Blue Line propels Lombardy into a greener, more accessible urban future.