Iron rolling on iron is cheap and low friction. Magnetic stuff is even less friction but mooooore expensive. Much more. Planes are high friction and need much more expensive energy. Forget cars, friction is killing their efficiency.
When you optimise for cheap and low friction trains are king.
It’s not just friction, it’s also the space per passenger (aka number of passengers relative to vehicle size). That’s why airplanes and bicycles work too, despite not being iron rolling on iron.
Iron rolling on iron is cheap and low friction. Magnetic stuff is even less friction but mooooore expensive. Much more. Planes are high friction and need much more expensive energy. Forget cars, friction is killing their efficiency.
When you optimise for cheap and low friction trains are king.
It’s not just friction, it’s also the space per passenger (aka number of passengers relative to vehicle size). That’s why airplanes and bicycles work too, despite not being iron rolling on iron.
Planes have a historically bad record testing their friction coefficient against iron
Usually rather short tests.
Bikes are low friction as heck, the rolling resistance of a wheel on a road is low with that small amount of weight.
So yeah, amount of machine per passenger (which in a car is often only 1 person) and amount of infrastructure it takes to support that per person
Friction isn’t bad, it just defines starting/stopping distance.
It also defines energy loss at speed.