isn't the idea that trucks will be self-driven? in that case one company will own multiple trucks. in the meantime, if you are independent driver who own's the truck, you could be switching trailers with different cargos. you deliver the trailer to some point, unplug it, recharge, plug in different trailer and continue to its destination.

or are you asking me if I own a track and how the mechanics of truck/trailer works?

no i don't own the track and this https://upload.wikimedia.org/wikipedia/commons/thumb/3/3e/Co...