Re: Tesla semi?
"...and we could run them on special tracks so they could be much longer with a whole series of trailers. They would need to be more powerful for the long train of trailers. But, instead of batteries, they could take power from overhead lines."
Or, they can have batteries And a diesel engine And work from overhead lines depending on where they are while running on special tracks for less rolling resistance. I bet that those would be much easier to automate.