I can tell you that line 9 is nothing like the the privatised transport system in the UK (I have lived most of my life in UK, and 7 years in Seoul). It costs ab

I can tell you that line 9 is nothing like the the privatised transport system in the UK (I have lived most of my life in UK, and 7 years in Seoul). It costs about 65p to ride, 75p for the express train, it's clean, safe, comfortable, modern, spacious. The stations are accessible, welcoming, and full of conveniences. Transferring to or from a bus is free. Ticketing is contactless, convenient, uniform across the whole country. It's like a cheap, modern, less cramped version of the best lines on the tube. All the other lines are mixed private/public and they run very well. The story here isn't as simple as "public good, private bad, mixed worse." As with many things in life, it all depends on the actual details.