Self driving train seems like a no brainer. I suspect that even with the tech 10 years ago it could have been solved. Where are they and why isn't someone working on it?
I suspect when something is this obvious, yet we don't see a product, it has to do with someone in the industry fighting change and making sure it does not happen.
Rail already has a tremendous labour advantage over trucking. The principle limitations seem to be net transit speed (freight moves on average at or below 30 mph net, and peaks at 79 mph in the US) and the sheer delay and confusion in arranging shipments.
Freight's worked well for high-volume bulk commodities (coal, grain, tanker cars). Intermodal ("piggyback" or containerised cargo) works quite well, but still sees delays compared to trucking, and generally is not viable for distances under 500 mi / 1000 km (within the US). Sub-car shipping (equivalent of less-than-truckload or LTL for trucking) is a nightmare for shippers.
Rail doesn't seem to be integrated into much consumer logistics. Yes, the net flows are slower, but it's far less energy intensive than truck-based shipping (or air cargo), and should be far more economic. The logistics and scheduling though seem to be a real concern.
Trackage consolidation's been an issue, there's been a net decline of trackage for most of the 20th century AFAIU. That especially includes suburban and urban centre transport.
Railyards are still large-area operations which are expensive in terms of locked-in real estate within urban regions. There are major crossing points and exchanges (including both ports and mid-line switching operations) which have been major choke-points.
The basic technology works. It's tremendously efficient. It actually is a largely un-sung success story in the US. And yet it seems it could be so much better.
Probably little savings in just outsourcing that one (small team of) humans to AIs, and you lose your custodian for negotiating out-of-the-box situations. Seems easy enough though.
I suspect when something is this obvious, yet we don't see a product, it has to do with someone in the industry fighting change and making sure it does not happen.