They mention it only offhand in one sentence, but my understanding of most of the slowness of the US rail network is that it's mostly passenger trains having to

They mention it only offhand in one sentence, but my understanding of most of the slowness of the US rail network is that it's mostly passenger trains having to let long freight trains pass that eats tons of time. Nominally, passenger trains have priority and freight trains have to pull into a siding to let them pass, but freight companies made the freight trains longer than the available sidings and so it's the passenger train that gives way in practice most of the time. Doesn't really matter how fast the train is, or how efficiently it's boarded if it spends excessive amounts of time sitting still waiting for freight to pass.