We had cars on rails. It doesn't really make sense: The train is much heavier, thus has much lower acceleration and lower max speeds. The mass & area needed pe

We had cars on rails. It doesn't really make sense: The train is much heavier, thus has much lower acceleration and lower max speeds. The mass & area needed per person is also much higher, increasing fares a lot. Terminals & stops need to be much larger and take longer. Self driving doesn't improve on any of this, even worse, it takes away the major advantage of not needing to drive. There's a reason loading cars on trains as a way of travel is basically dead and self driving makes it worse.