Milan Completes Full 15-Kilometer Metro Line 4 Opening as San Cristoforo FS Directly Connects to Linate Airport Across 21 Automated Stations

Transforming Metropolitan Mobility with the Complete 15-Kilometre Blue Line

MILAN, Lombardy — In the most significant enhancement to Northern Italy's public transportation network in decades, the Municipality of Milan (Comune di Milano) and public transport operator Azienda Trasporti Milanesi (ATM) have celebrated the full commercial commissioning of the entire 15-kilometre Metro Line 4 (Linea M4 - Blue Line). With the completion of the western segment linking San Babila to the railway hub at San Cristoforo FS, the automated underground railway now operates continuously across 21 modern stations, establishing a seamless high-speed diagonal axis that connects Milan's western rail corridors directly to Milan Linate Airport in the east.

The full line opening slashes cross-metropolitan journey times to just 30 minutes, allowing passengers to travel directly from outer suburban commuter train connections into the heart of the historic center and onward to international flight gates without stepping foot into automotive traffic.

Driverless GoA4 Hitachi Fleet and Automated Platform Screen Doors

Constructed by a consortium of leading European engineering specialists and operated under a public-private partnership, the M4 deploys a high-efficiency fleet of Hitachi Rail driverless trainsets operating at Grade of Automation 4 (GoA4). Without human cab drivers, the automated system utilizes sophisticated Communications-Based Train Control (CBTC) signaling to safely coordinate train movements, enabling minimum operational headways of just 90 seconds during peak morning and evening travel windows.

Every underground station platform features full-height glass Platform Screen Doors (PSDs) that synchronize flawlessly with train vehicle doors, maximizing passenger safety, preventing accidental falls onto tracks, and enhancing climate efficiency by sealing subterranean station concourses from tunnel draft air currents.

Major Interchanges at Sant'Ambrogio and Sforza-Policlinico

The final operational phase delivers vital transit interchanges that seamlessly knit together Milan’s metropolitan rail network. At Sant'Ambrogio, passengers can transfer directly between the M4 and the Green Line (M2), providing fast access to the Catholic University campus and Cadorna station, while the Sforza-Policlinico station provides direct pedestrian interchange tunnels to Missori on the Yellow Line (M3) and the expansive Ca' Granda healthcare campus.

At the western terminus of San Cristoforo FS, the station interfaces with suburban rail lines (S9) and regional passenger services, providing hundreds of thousands of commuters arriving from southwest Lombardy with immediate, turn-up-and-go metro transit into central commercial, fashion, and financial districts.

Eliminating 180,000 Daily Car Trips and Cutting 10,000 Tons of CO2

Engineered with regenerative braking systems that feed captured deceleration electricity back into the power grid, the M4 is estimated to divert upwards of 180,000 private vehicle journeys daily from Milan’s congested street corridors. Municipal environmental models indicate the line will reduce annual automotive carbon dioxide emissions by more than 10,000 tons while substantially curbing particulate matter levels across the metropolitan basin.

Milan civic leaders and regional transport authorities emphasized that completing Line 4 elevates the metropolis into an elite tier of sustainable, fully connected European capitals, providing an enduring foundation for economic productivity, clean urban living, and world-class public mobility.