Trains are like the old mainframes. They should be more efficient than a car, but in practice they aren’t.
Like a PC, the car has the advantage over the train of:
- distributed, not central, control
- variety of type to suit different and unknowable needs
- many competing suppliers.
Cars share a road system with only a few enforced rules. They interact with each other with a complexity and subtlety that no designer could possibly foresee. They use the road infrastructure much more intensively than trains can use rail. Overall, although they are obviously a sub-optimal way to travel, they beat the train for most people most of the time.
Like a mainframe, a train has the advantage in a few situations:
- when the load is very heavy
- for predictable, repeated loads
- when you are not paying for it.
Transport engineers are like IT people. They would much rather everyone used the train. But in practice they spend their time dealing with the unpredictable world of the car.