Full Coal Trains Use Less Fuel Than Empties!?

I found this interesting. I'd start the video at 4:15.

https://www.youtube.com/watch?v=-R3ZoeZ95Yc" onclick="window.open(this.href);return false;

Any thoughts?

Well, on the one hand, railroads are VERY efficient at moving heavy loads. On the other, never underestimate the effects of aerodynamic drag! When the French railways set the world rail speed recorder in the 1950s (two runs of about 200mph with two different electric locomotives),a major part of slowing the test train down was… opening the windows in the carriages!

If it's the drag from the open tops of the empty coal hoppers causing the extra use of fuel then couldn't the railroad save considerable fuel just by covering up the empties?

Sure but then you have to factor in the purchase price of the covers, the labor cost to put them on, the time and labor to move covers around the system to where they're needed, and most importantly how much time it would take to put the covers on an entire empty train.

If the loads are rolling gently downhill, say 0.2% would be nice, they might well use less fuel than the empties returning upgrade. The guy didn't say what territory he was talking about, did he?

No reason to think empties use more fuel on the level than loads on the level, at the same speed.

Im not a railroad guy but if you think about maybe it takes 2 locomotives to pull an empty 100 car train vs 4 locomotives to pull a loaded 100 car train. So one would think 4 locos would use more fuel. Maybe the guy was talking about running down hill.

The problem is the cumulative effects of slightly more aerodynamic drag on the empties, plus normally higher speeds of the empties to reduce cycle time, plus if the loaded train requires extra locomotives they won't appear at the coal mine by magic so the empty train has to bring them along. People talk about the space between containers on a doublestack train, well there is a lot of empty space inside an empty train of coal gondolas.

It's had to imagine just how much drag there is on an empty coal train. The empty train will slow down just by reducing throttle.

The aerodynamics of an empty makes sense as the full load the air won't swoom around in the car, when the coal drag is moving it has its own weight of inertia to keep moving and the mounds of coal produce reduced aerodynamics with some streamlining effect. May as well make new coal cars with closeable streamlined designed tops.