Milan Celebrates Transformative Mobility Milestone as 15-Kilometre Driverless Metro Line M4 Achieves High-Frequency Operations Across 21 Stations

Connecting Milan Linate Airport Directly to San Cristoforo FS in 30 Minutes

MILAN, Lombardy — In a generational leap forward for urban transit and environmental decarbonization across northern Italy, the Municipality of Milan and municipal transit operator ATM (Azienda Trasporti Milanesi) are celebrating the operational success of the completed Metro Line M4 (Linea Blu). Spanning 15.2 kilometres and 21 state-of-the-art underground stations, the driverless automated rapid transit line forms a seamless high-speed axis linking Milan Linate Airport in the east directly through the historic city centre to San Cristoforo FS in the south-west.

With trains whisking air travelers from Linate Airport directly to the central transit node of San Babila in just 12 minutes—and traversing the entire cross-city alignment from terminal to terminal in 30 minutes—the Blue Line has redefined regional accessibility. The corridor connects major commercial districts, prestigious university campuses, and dense residential quarters, transforming the daily commutes of hundreds of thousands of residents and business visitors.

Driverless Automation and Communications-Based Train Control (CBTC)

Built by Italian engineering giant Hitachi Rail, the M4 operates with fully automated, driverless trainsets adhering to Grade of Automation 4 (GoA4) standards. The subterranean stations feature full-height glass platform screen doors that open synchronously with train doors, eliminating platform fall hazards and enabling ultra-precise train headway intervals of under 90 seconds during peak commuter rush hours.

The system utilizes advanced Communications-Based Train Control (CBTC) radio signaling, which continuously calculates optimal acceleration and regenerative braking curves. This computerized precision slashes electric traction power consumption by up to 20 percent compared to legacy manual metro lines while capturing braking energy to feed auxiliary station electrical networks.

Slashing Private Car Trips and Curbing Urban Carbon Emissions

City environmental monitors and transit analysts report that the operational maturity of Line M4 is delivering extraordinary ecological benefits for the Lombard capital. Carrying over 150,000 passengers each weekday, the line has displaced approximately 180,000 private vehicle trips per day across Milan's congested arterial ring roads.

This decisive modal shift eliminates an estimated 10,000 tons of greenhouse gas emissions and significant particulate matter (PM10 and PM2.5) annually, dramatically improving urban air quality and advancing Milan's binding climate transition roadmap toward net-zero municipal emissions.

Advancing Eastern Extensions Toward Segrate Porta Est and Idroscalo

Building on the triumph of the core line, the Lombardy Region and Milan City Hall are advancing planning and preliminary engineering for the next evolution of Line M4: the eastern extension toward Segrate Porta Est and Idroscalo. The planned two-station extension will link the automated metro directly into a brand-new high-speed rail interchange station at Segrate, providing direct transfers to regional trains and high-speed Frecciarossa services.

Milan civic leadership emphasized that the complete operational delivery of Line M4, paired with forward-looking regional rail integration, cements the city’s reputation as one of Europe’s premier capitals of sustainable mobility, green engineering, and world-class urban infrastructure.