To take the pipe loads question a bit further, I suspect that since the pictures were taken in Sparks, Nevada yard, that the original source was from the Napa Pipe located in, Napa California.
The load was originally handled by the California Northern Railroad out of Napa Junction to Busch/Fairfield where they interchanged with UP.
Napa Pipe has numerous loads going out and the process is fascinating to watch. One or two GP15-1's straining to pull 15-20 or so loads of steel pipe is a site to see.