Cost per passenger per mile is cheaper by rail than by road. It is just much more efficient.
If we then start to take into account the other costs such as pollution, land wasted on parking and wider roads, the increased area of municipal services that have to be covered because of the much lower density require for cars, and the massively increased health costs associated with a car lifestyle and trains not only are more cost efficient than cars they're an order of magnitude more cost efficient.
Trains are wildly efficient, they only use energy to overcome air and rolling resistances as energy used to accelerate is put back into the system during deceleration. They can pack many more people with much higher throughput. For example Crossrail in London is designed to have 24 1500 person trains an hour on a single track.
Highway costs less per lane than a single line of rail but considering most highways are 3 lanes either side the cost factor starts to become favourable to railway lines.
If we then start to take into account the other costs such as pollution, land wasted on parking and wider roads, the increased area of municipal services that have to be covered because of the much lower density require for cars, and the massively increased health costs associated with a car lifestyle and trains not only are more cost efficient than cars they're an order of magnitude more cost efficient.
Trains are wildly efficient, they only use energy to overcome air and rolling resistances as energy used to accelerate is put back into the system during deceleration. They can pack many more people with much higher throughput. For example Crossrail in London is designed to have 24 1500 person trains an hour on a single track.