I can see that too, but only after all the logistics are worked out. It's a neat idea, for sure, but I anticipate that many shortline RR's will not want to hand over millions to upgrade signals, and such. And it doesn't address what happens to passenger trains on some of the railroads, as many Class I's have some passenger service.
Maybe we could get our own personal "self-driving" passenger train cars to transport us to wherever we need to go. My guess is our cars will be self-driving first (once all the current kinks, etc. are worked out). But, it's nice to dream.