"Anybody notice the crew is riding on footboards in the fourth photo?"
Good eye, young Grasshopper.
There was an overlap of rules from the time the FRA took up dealing with footboards and the riding thereof.
At first, riding the footboards was disallowed on a FORWARD movement. (Hence A.W. riding the rear footboard on a forward movement.)
Soon, riding footboards was off limits period. Shortly after, it was required that footboards be removed. Therefore, footboards begin to disappear (and disappeared fast) sometime in 1978, as I recall. Within a short while, they were pretty much all gone. Another one of those things that happened fast once the law was passed.
Wow. All this railroad knowledge being spewed at this forum means that we can all learn about railroad history and the evolution of safety appliances, or whatever... even down to the trivial level!
Downside is that all this newfound knowledge can make you a nit pickin' rivet counter, if you're not careful.