I'm not sure about the congestion point. There has not been a railroad system that supported anything like the volume of travel that is currently supported by the automobile.

I think one must be careful about the train versus car efficiency argument. Trains, for example, are big. You get a dining car, aisles to walk around in, lots of extra space that you don't get in a car--and that needs to be carried around with the people. Also, the fixed A-to-B routing with intermediate stops means that at the ends of the run the train may be mostly empty--something every tram or train commuter is familiar with. And it's true that steel wheels on steel rails have very low friction, but low rolling resistance car tires have low friction--and it's a space that has not been fully explored by the technologists.

But again, the point is that perhaps trains ARE more energy-efficient than cars, but even so, if people are willing to pay more to have the flexibility of the car, it is worthwhile to allow that--if in both cases they meet the broad social objectives.