Such a subway already exists, in the capital of North Korea! https://www.youtube.com/watch?v=9hxVWjW4TuM https://www.youtube.com/watch?v=9hxVWjW4TuM I would b

Such a subway already exists, in the capital of North Korea! https://www.youtube.com/watch?v=9hxVWjW4TuM https://www.youtube.com/watch?v=9hxVWjW4TuM I would be happy if municipalities simply cleaned and maintained public spaces like subways. It's possible, but it's a boiling the ocean problem. Homelessness, mental illness, vicious youth, all in a context of ever-decreasing public infrastructure investment and bitter inequality of resources and opportunity-- it doesn't help make for a clean subway system.