DRD, yes you are absolutely correct as always. I didn't bother mentioning why I am interested in the subject. Because I noticed walking machines such as the Chebyshev's plantigrade could be easily adapted to running on tracks. The machine can be made very lightweight, so in turn the rails can be made from wood, plastic, concrete, aluminum, whatever is available, and raised 8 feet on trestles to eliminate hitting pedestrians, animals, flooding, washouts, potholes. When I see current efforts at autonomous vehicles designed to operate on asphalt roadways, I see a machine that should be on rails, because keeping the car between the lines is exactly that. It's a waste to pave 20 feet wide roads when vehicles have a footprint a few inches wide. It costs around $one million to build a road and $28k per year to maintain it. I am convinced a super light rail network can cost less than 1%. And the traffic can be vertically stacked to take up less real estate. 25mph for the low level at 8 feet, 50mph the next level, and 75 mph at the top. Using existing power transmission corridors, and marrying autonomous vehicle systems, crash safety systems would be unnecessary
Currently tracks can cross each other at various angles, I just think it's possible to switch if the angle is shallow enough.