Fun fact of the day, the American Federal Railroad Administration is so understaffed and stretched thin if barely has an idea what is being transferred on the US's massive rail network. It could be people it could be a hazardous chemical, they only know when the railroad companies (that exist as little more than dividend checks for shareholders) tell them.
The next time your insane libertarian uncle tells you the government is spying on you know that they barely know what is on the rails that go through major population centres every day.