I don't know about this route in particular, but Amtrak generally runs on freight lines. It's quite possible that the time lost to stopping to pick up a couple

I don't know about this route in particular, but Amtrak generally runs on freight lines. It's quite possible that the time lost to stopping to pick up a couple passengers is dwarfed by the time spent sitting on a siding waiting for freight trains to pass (I've spent many hours of my life here).