>public parks, public litter bins, public roads These examples are permanent things, that only need to be maintained, and it's easier to just let the government handle them instead of letting the individual pay or having a subscription model or something alike. Also: all the public goods you mentioned cannot be managed by any single individual, that's why they are in the public hand, but it only goes so far as your activity is in "public range". You can't pave your own roads, you can't carry a trash can with you wherever you go and you can't play football in your house. That's why the government gives you roads, parks and trash cans. But: it is not allowed to put your house trash into a public bin. Or have a barbecue in the public park, or block the roads for a protest.

I think using the train is more like using the car. I can agree that the tracks are a public good, but actually using the train is clearly different from that. Just like the government provides me roads, but not with rides.

> I don't think I've ever seen planes classified as public transport I guess my framework fits that, because while you may need to maintain the air and the airport, the individual flights only help the individual person.