Combine this with the Ohio derailment and the uncaught substation snipers which knew an awful lot about what equipment to take out.
Derailment is a powerful sabotage tool. Americans were caught attempting it in Russia years ago. https://tass.com/politics/1313063
They are trying to weaken infrastructure by making taxpayers bleed time, money, and effort.
Someone in another post was worried about balloons dropping bombs. Guided glide bomb would be pretty effective. But the balloon isn’t stealth. As we’re seeing, even small objects can be tracked by radar. Also, bombs are heavy and that means a large balloon. Something the size of the ground visible spy balloon.
Infrastructure is more resilient than you think. I doubt there is a spot where a single bomb could cripple things. If there was, a ground bomb would be effective and easier.
And, forensically, what’s left behind after an explosion tells the design and mix of fissile material, which tells you the level of resources available to the maker.
Not sure I believe that it can be done beyond a reasonable doubt. I still don't see what evidence there is that these things are Chinese. It's probably speculation and nothing more. It might still be true, but the attribution is likely highly speculative.
Another thing is that other countries have radar. They likely tracked the balloon but ignored it. Russia probably won’t help but Japan might have seen it. Also, US is tracking balloons from before they enter Alaska.
We know the balloon is Chinese because they claimed. We don’t know what the other objects were.