Rail/River/Ocean Transport

[Groucho]

For river/rail/ocean transport the tooltip gives two numbers seperated by a slash.

They are listed as current/maximal.

What exactly do these numbers represent and what causes them to fluctuate?I keep pumping resources into river and rail transport and I don't actually know where it is all going. Do RR engines and riverboats break down? Is that why the number keeps going down? I am not looking to micromanage. I just want to know where my resources are going.

I once had an expeditionary force besieging Wilmington, NC and they were not getting resupplied. Is it because I did not capture the forts outside the harbour?

[Gray_Lensman]

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