Buffett's comments about railroad efficiency

This may help.
Fuel-Efficiency - CSX

 

Here's another link .
Fuel-efficient transportation: An overview | MNN - Mother Nature Network

 

Low rolling and air resistance, but mostly economies of scale.

If you want another mind-blowing figure, calculate how many lbs per horsepower a typical freight train results in.

 

It is worse than that, your car doesn't carry a ton of cargo. Fully loaded, it should be a bit under half a ton. So you'd better think about getting 1000 miles to the gallon for that half ton.

But look at the differences. In a car at highway speed, much of that fuel gets put into shoving air out of the way. On rail, that same effort gets shared with a thousand other cargo loads, so is split many ways.

And rolling resistance. Steel wheels on steel rails have much less rolling resistance that rubber on asphalt or concrete.

Add in a far better ratio of payload to vehicle weight, shallower hills and generally flatter routes, less speed variation due to traffic congestion, more efficient engine controlled closer to its best operating efficiency, (usually) no climate control or other accessory loads, and things really add up.

 

The trains run from flat (o% grade ) to a max of 3% 140 ft per mile. If all the roads were built that way , we would all get huge mpg's.

 

I think they are using the diesel electric hybrid plus other variables that makes a locomotive very efficient. This is explained more in the video link. How a Modern Hybrid Locomotive Really Works: Video - Bloomberg

 

Freight means cargo. The weight of the vehicle cannot be unloaded and put on a dock. It cannot be counted.
We are talking about freight efficiency not vehicle efficiency.

 

But your original question was about Buffett's trains "carrying a ton of freight about 500 miles on a single gallon of diesel fuel."

Are we talking about freight or not?

 

Because of OP comments don't count the weight of the train itself, only the weight to the paying cargo.

 

In freight?
There's also the first mile/last miles to consider.
Naturally they leave these costs off of the equation.

Yes.
Freight is about the second most cost efficient way to move things from here to there.
Just remember....
You still need trucks.

 

IMHO, using an unloaded Prius is not a bad example. You're basically just making a simplifying assumption that all the Prius' weight is cargo, or in other words the ratio of the train's empty weight to loaded weight is approaching zero. That introduces an error, but is not a bad assumption to get a rough ballpark number.

I would guess the biggest difference is hp to weight. In a train rolling and aero losses are very low as mentioned above, and its acceptable to go 0-60 mph in 5 minutes. So they can run about 1hp per ton. If you could somehow get the rolling and aero losses on a Prius low enough that you could accelerate to 60 in 5 minutes with a 1.5hp engine, then 300mpg probably wouldn't be far fetched. As it is, with realistic rolling and aero drag it takes around 20hp just for a Prius just to maintain 60mph constant speed.

 

this will blwo your mind...

a 10,000+ TEU Ship. a TEU is one 20' Shipping container (or basically 1/2 of a standard Tractor Trailer.

Is designed to run @ 24knots and will burn 300 tons of fuel per day. thats 576 miles or 1.9 miles per ton of fuel.

One ton of fuel is 621 gallons. So 621 gallons to go 2 nautical miles.

so a 10K TEU ship is essentially 5000 tractor trailers... now take the fuel.. 621 gallons...

.12 gallons per truck per 2 miles. or about 20 miles per gallon...


Ultra large Containerships are 14K TEU and above... whichmeans theygetthe equivalent of close to 40 miles per gallon per tractor trailer..

tractor trailers can carry about 36,000 lbs or 18 tons... not as impressive as trains, but still pretty neat numbers...

if i did my math right.....

 

In my old Army days I ran across a logistics planning rule-of-thumb: most efficient way to ship heavy Army supplies (all nine military classes of supply) from CONUS into an overseas theater of operations: by ship. Most efficient way to distribute same nine classes of supply between the seaport and the forward operating area (combat conditions dependent): by train. Most effective and most flexible (but not most efficient) way for the last 50 miles from the railhead to the end user units: by truck. Of course, this planning rule also allows for the time & labor cost of transloading at each modality changeover, i.e. larger (ship) to smaller (train) to smallest (truck).

This also illustrates the cost the Allies bore after blowing all the targetable French railroads and rolling stock in NW France from the air during the prep for the 1944 cross-Channel invasion of Europe. As the Allied Western front advanced up to and beyond Paris in 1944, the Anglo-American logistics command converted the two major Paris - Normandy highways into all-lane unidirectional routes: the loaded one was "All East" and the other, empty one became "All West" to keep the trucks rolling 24-7 with dedicated trucking battalions. I read that eventually this Red Ball Express effort consumed idiotic amounts of fuel to keep the frontline supplies going - fuel that was carried on the Red Ball Express trucks along with other cargo. This persisted into early Winter 1944 - 45 when the Western front stabilized.

So yes, just based on that planning rule a cargo train is enormously more efficient at moving cargo than even(!) a Prius. However, for that last 20+ miles from the store to the house a Prius can't be beat.

This also helps to explain the enormous and unseen burden we have assumed during the last 12 years by projecting large forces into Afghanistan, a land-locked country with nearly medieval transportation infrastructure, where we had to transport the immediately needed military supplies long distances into the country by air transport, just about the least efficient logistics resupply method there is, or alternately by looong and dangerous trucking routes across most of Pakistan. All the while our sometimes-allies the Russians just couldn't be bothered to allow us and NATO use of their extensive railroad network for Afghan resupply until just two years ago or so.

 

Just for the fun of it, assume you bring back 20 lbs of grocery from the store to you house and getting 50 mpg from the Prius. Then fuel efficiency for the payload =
50 mpg * 20/2000 ton = 50 *0.01 = 0.5 mpg per ton.

This is the least fuel efficient leg the grocery trip to your house.