As both a car and railroad guy, I will point out that we are at a crossroad. The gasoline internal engine will not get anymore efficient than it is now. Look at fuel economy. A 350 v8 gets if lucky, 13 mpg city, 20 on the Hwy if you really feather the gas pedal. That’s today with all the fuel efficiency crap that they put on it. My 1968 Mustang 289 v8 did the same mileage 40 years ago when I drove it. The next generation of cars either are going to be electric, hydrogen (if they can get the stations set up nationwide), Steam, or some other clean fuel.

To make this rr related, the steam engine was not efficient, diesel-electric is not efficient, and electric will get there if generation can be done without killing any animal that pisses off the environment.