Um, what are these doing in North Dakota?

Posted by a friend, to a friend, of a friend, to a friend, looking for answers to this question. WHAT the heck are all these doing going through North Dakota? I'm sure this is how they transport them, but the question is where is the nearest tank manufacturing area? Geesh. You'd think they'd wanna minimize the amount all at once, unless the shit's truly about to hit the fan. Way to go, Stuipid ass Joe!