Ken is wrong as far as I know, for posted speed limits (as opposed to actual speeds, or maximum possible engine speeds) on a speed board or in a published employee timetable. Nor, as far as I know, is there any evidence for a published scheduled average passenger trains speed faster than that.

I have never seen a speed higher than 79 mph listed in any of the older employee timetables I have for any segment of the SP, but I would love to see the proof, if it exists?

Yes, SP did much better than Amtrak does, or has done on the Coastline. They didn't pad the schedule with an 20 minutes extra for each hundred miles like they have today, or for "smoking breaks".

I have heard numerous stories about SP trains doing 90+ making up time, and many are certainly true, but that was not a "permitted" or a posted speed.

I myself took a BSMFF with a dynamiter and only two working dynamic brakes down the Acolita grade into Niland with my speedometer pegged on 90 mph.. That distant signal approaching Niland would start as a flashing yellow, and I figured if it didn't go green, we would have to plug it there to be able to stop before the fouling point at the west end of Niland.

I also had two "shut down" cars for Gemco, with four units and a caboose. And, the Road Foreman told me there was no speed limit, and we probably approached 100 mph past the end of Two track leaving Yuma. before he gave me a look of terror and I backed off a bit.

An old hoghead once reminded me, when I was a young hot running fireman, "that any fool can run one of these things, but that they paid us the really big money for being able to stop them....".