https://en.wikipedia.org/wiki/9_de_Julio_(Line_D_Buenos_Aires_Underground)
https://en.wikipedia.org/wiki/Line_D_(Buenos_Aires_Underground)
https://en.wikipedia.org/wiki/Buenos_Aires_Underground_rolling_stock#Current_fleet
The train & the bus can work very well together as the backbone of an urban transit system.
https://en.wikipedia.org/wiki/Avenida_9_de_Julio#MetroBus_Line