it's in context of the first comment i made, which is at the top of this particular chain of replies. but i'll reiterate: the idea of autonomous bogies is fundamentally tone-deaf to how rail works, it solves no problem and creates lots of new ones. they are not useful in rail yards since they can not be used as shunters nor in any way help to build cossists, they are not useful for last-mile because the sidings don't exist and they're not useful for the first 99 miles because their range is abysmal.

also they can only take containers, require new infrastructure for charging, and take up slots that could be used by full trains.