The last one is connected to the internet and this is why you can see (or at least before the pandemic could see) Instagram posts from North Korea.

I have no idea if this information is still or ever was completely true though.

There's a somewhat dated but very interesting AMA on Reddit by an American teaching computer science in Pyongyang:

https://www.reddit.com/r/IAmA/comments/1ucl11/iama_american_...

Reading about the internet knowledge possessed by North Korean students, I'm always surprised how they supposedly also manage to be some of the most cunning and evil actors when it comes to hacking.

North Korea is responsible for adding the hot beverage, umbrella with raindrops, and lightning bolt emojis

https://en.wikipedia.org/wiki/KPS_9566

Edit: Good article though, I enjoyed it a lot.

As for utility boxes along the track, it could be something railway-related, for example, some railway control or monitoring equipment.

also a ditch witch and couple of support vehicles could run cable through most terrain, and in agrairian areas , not needing permits and such, would be indistinguisashable from other activity ,happen very quickly, and leave no trace

humanity has reached the point where our comunications net is a given for 90%+ of the population centers in one form or another, and if not for the slop, would have an order of magnitude, excess capacity. throw in peer to peer ,and the soon to be blanket coverage from sattelite swarms, and well, what? sonar relays for underwater, and seizmo transmitters