Last month, President Obama announced an initiative to improve the fuel efficiency of trucks. That’s a lofty goal, but here’s an even better idea: Let’s make an effort to move more freight by rail and less by road. Trains are far more energy-efficient than trucks – and they always will be.
Trains have a significant friction advantage over trucks. The degree of “stickiness” between two surfaces is expressed mathematically as the coefficient of friction. For a steel wheel rolling over a steel rail, its value is approximately 0.001. For a rubber tire rolling over pavement, the coefficient is between 0.006 and 0.010, or roughly an order of magnitude greater. Some friction is good – it stops the vehicle when a person runs out in front of it. But too much friction means less energy driving the vehicle forward.
Read the complete story at The Washington Post.