The train example is a pretty bad one, I'm the first in four generations not to work for the local railroad and five union dudes on a train crew pretty much went away in the 1970s. You do typically have two guys and you really need two for safety as sometimes you need human eyes looking out both windows at once (freight trains have poor visibility compared to trucks).
A freight train with one dude strikes me as unlikely. The few single person trains out there have excellent visibility for the one driver. So you'd have an interesting capital expense if you tried that with freight trains. I do know some small switcher locos run single person but thats in a barb-wired switchyard well away from the general public. So you'd "have to" eliminate all grade crossings or something, another big expense.
A freight train with one dude strikes me as unlikely. The few single person trains out there have excellent visibility for the one driver. So you'd have an interesting capital expense if you tried that with freight trains. I do know some small switcher locos run single person but thats in a barb-wired switchyard well away from the general public. So you'd "have to" eliminate all grade crossings or something, another big expense.