I just did an Amtrak Southwest Chief journey from Fullerton, CA to Naperville, IL and back.
On the eastbound journey the amazing thing is we were routed around freights on the double track mainline through California - Arizona and the western part of New Mexico. We were never held up by a single signal…well other then slowing to 40mph to cross over to the other main and back again. There is no freight traffic on the Raton pass line so nothing to report there other then worsening track conditions.
But oddly once we got onto the mainline again in Kansas, we were no longer being routed around the freights, but following them. And as a result we lost significant time.
Westbound was similar.
So I think a lot has to do with dispatching centers and overall traffic conditions.
All I know is that whatever BNSF is doing out west they should keep on doing it. Fast passenger trains and freights. Not so sure about the eastern portion of their line.
The Empire Builder line is a real problem. Significant portions of the route are not double tracked so loads of problems stack up. Especially with the oil boom in the Dakotas.