You're moving the goalpost and earlier insinuated that tunnels for subways require lining and other fire suppression systems. They do not. The automated sprinklers are needed for stations, but not the tunnel itself. Same for standpipes.
The insulation for cables are a given, because you will need it for ALL tunnels. Not just HV cables, but ALL cables, including fibre and low-voltage cables.
Thus, no difference.
> Tesla doesn't use LIDAR but they do use ultrasonic sensors. Tesla's existing autopilot systems works just fine on completely dark, unlit roads. I don't see why these skates would be any different.
Does Tesla's existing autopilot system using LIDAR/ultrasonic cameras have automated collision protection that does so without having to communicate with the other cars behind it traveling at 120mph to 150mph? No. You will need to modify the system to do this, and you will need to add the mesh network to the tunnels, among other things I described.
> Even with fibre and low voltage power for access points (if even needed), you're still leagues away from the cost and complexity of a full tracked third-rail system.
Agreed. Tracks and third rail are not cheap, comparative to not using them at all.
> I'm not sure what you mean. Flexibility is cheaper. Being able to use a tunnel that is 500 feet long at a 10% grade is cheaper than having to build a tunnel that is 1500 feet long at 3% grade.
How? If the total length of the overall tunnel is the same, the cost of materials are not substantially different.