Travelled most of this rail system, as I often do in new places. For me, the numbering of the station's made navigating easier.
Some stations in affluent areas were clean, modern, impressive.
Others were filled with crowds, street vendors & food stalls.
Still others were downright dirty and scary. Trains move fast, mostly on time, but often hard to get a seat. While the routes are long enough to be considered intercity commuter rail in the US, these are standard gauge subway cars with bench seats and strap hangars. Still, video in the ceilings, announcing in multiple languages, and Air Conditioned cars! I wish the maps on the walls of the car were larger print so you could read station names from a few feet away.