Why is shipping more efficient than rail?
I'm aware that measured in ton-miles per gallon, ocean shipping is the most efficient mode available. The question's arisin: why?
Sources: various but typical, "Comparison of Different Shipping Methods".
So: what are the major elements of efficiency loss for ships vs. trains?
On my candidate list:
- Acceleration and braking: oceangoing ships move at constant speed.
- Grades. There are few mountains on the ocean.
- Drag: Water vs. rail vs. air.
- Powerplant efficiency: again, constant output means engines run at maximum efficiency.