The Milan Metro Line 4 route has 21 underground stations, including Segneri and Dateo, the latter of which opened in 2002.
The line will be 15 km (9.3 mi) long with 21 stations. Segneri Dateo It opened in 2002 as part of the Milan Passante railway. However, delays in planning, financing and construction works forced to postpone the opening, and the line is now expected to open between 2021 and 2023. Line 4 is a new underground rapid transit line under construction in Milan, Italy, part of the Milan Metro. 
