> Besides, if we are just on the cusp of having self-driving cars we should be able to deploy self-driving trains right now and reap all the benefits of autonomous transport immediately.

Self-driving (GoA4) trains are close to 40 years old: https://en.wikipedia.org/wiki/Kobe_New_Transit https://en.wikipedia.org/wiki/Lille_Metro

We are. In London the DLR is the most obvious driverless network, but various parts of the Tube have been essentially driverless since the 1980s (initially on the Victoria Line, then on the Central after its resignalling, and on the Jubilee extension).

Many cities use automated light rail or subway systems. Vancouver, Canada has has such a system in place since late 1985.

https://en.wikipedia.org/wiki/List_of_automated_urban_metro_...

Those exist in many cities. The train to/from the Airport in Copenhagen for instance has no drivers.

> self-driving trains

Should have had these for a while now.