BHSC: Thanks for confirming my belief that passenger trains have priority over freight. I'm only repeating what I've been told, but it seems to fit. I'm most familiar with the Empire Builder, which starts in Chicago and ends in Portland or Seattle (it splits in Spokane). The only time I recall sitting on a siding for any length of time was when we were being passed by the Empire Builder going the opposite direction, and that only happens once a day, since the train only runs once a day—or it used to; I think they may have cut the schedule to less than 7 days a week.

I was offering that as an explanation for why passengers can go from coast to coast in less time than freight. Here's another reason:

It's a fairly simple matter for a passenger to get off one train and onto another at a hub such as Chicago. Freight can't do that. A freight train often ends up at a freight yard where all the cars are uncoupled from one another and shuffled around and reassembled into different trains going different places. The cars are moved around one at a time by switch engines. I don't know how long this takes, but I imagine it adds significantly to the travel time. I once watched a model-train enthusiast do this with model trains. It was agonizingly tedious. I didn't have the patience to watch until he was finished. I concluded the guy was obsessive-compulsive. I wanted to yell at him, Pick up the damn car already!

There's another kind of freight yard, called a "hump yard", where, instead of using switch engines, the cars are allowed to coast downhill, slowed by brakes built into the tracks, until they wind up on the right track. This is a bit faster.

More and more, with containerized freight, the train winds up at a yard where the containers are lifted off the cars by crane and onto other trains, or trucks, or cargo ships.

Then there are "unit trains" where the entire train consists of one kind of cargo (usually coal), going from one origin (the coal mine) to one destination (usually a coal-burning power plant). This is the cheapest way to move freight. You might think it would be more efficient to build the power plant next to the mine, and transmit the electricity over power lines to wherever it is needed, but apparently that isn't the case.

In northern Minnesota, unit trains are used to move iron ore from the Iron Range to ships in Duluth or Two Harbors.