I should clarify. When I said “all other forms of transportation”, that includes other trains. You can easily do it on a straight shot running back and forth. Which is what a lot of large airport trams do, and the monorail in Seattle (which is more like a bus on a concrete rail), but not much else.

As soon as you enter the complication of signaling, automation becomes a lot harder.

But yes, it’s not worthwhile to automate away that one extra job.