For a while now, CSX has been underwriting NPR with the tag line that they can move a ton of freight 436 miles on one gallon of fuel, or something to that effect (I may have the exact number of miles wrong).
Surely this can only be true if you subtract the amount of fuel it takes to move the train that same distance, right? I mean, it’s obvious they want to make it sound like you could put a ton of freight on a CSX train, put one gallon of fuel in the tank, and drive it 436 miles. But that can’t be so, can it?
But a train typically does not run with one ton of freight. It’s more likely to be a train with 4,366 tons of freight using ten gallons of fuel per mile. So if, for example, you want to transport 5,000 tons of coal from West Virginia to Chicago, rail is likely to be the most economical way. Or, if you have a box weighing one ton, you might put it on a train with a few thousand more tons of freight.
I’m pretty sure they get that figure by figuring out how many tons of freight they move (and how far they moved it all) and dividing by the gallons of fuel they used over a given year.
You’re kidding, right? Are people incapable of understanding the idea of “passenger miles per gallon” when talking about the difference between the efficiency of a busload of people and a car with only the driver?
I don’t think they take us for idiots. It’s up to us to show them!
Exactly. I think the natural meaning is that on a fully loaded train it averages out to a gallon of fuel per ton of freight over 436 miles. Anything else doesn’t make sense.
But once you do assume that they’re talking about averages, it makes plenty of sense. The three biggest losses of energy in a land vehicle are braking, air resistance, and rolling friction (not necessarily in that order). A well-scheduled train will travel for very long distances without having to brake, and even when it does, I’m pretty sure most of them have regenerative braking. Air resistance mostly just depends on something’s cross-sectional area, not its length, so every car past the first one is getting a mostly free ride, there. And rolling resistance is due to deformation of the wheel and/or the surface it’s rolling on, which can be reduced by making both out of a relatively unyielding material like steel. Given that all three of the primary inefficiencies are significantly smaller for trains than for cars, it’s not at all surprising that they get significantly better mileage per weight.
Thanks for the linky, Keeve. I attribute it to it having been early in the morning that I didn’t even think of Googling this.
To be honest, yes, I do believe they take us for idiots. Advertisers in general tend to cater to the lowest common denominator and if they didn’t, there wouldn’t be a well-known adage to the effect that “no one ever went broke underestimating the intelligence of the average person.”
The text CSX pays to have read does not say, “On average, our trains operate at 436 ton-miles* per gallon” because the average person** wouldn’t have the slightest idea how to parse that. They say “our trains move one ton of freight 436 miles on one gallon of fuel” (emphasis added). I think it is deceptive, howsoever mildly it may be so, and howsoever factually correct it may be.
All of this is IMHO, of course, and it should go without saying that yours may vary.
or whatever
** yes, even the average NPR listener, IMHO
I do not personally find it confusing or deceptive since only a very naive person would think the train itself is getting hundreds of mile per gallon of fuel.
However, in fairness to you, one could argue that if it’s OK for CSX to present their numbers like that, it’s OK for Honda to say my 8 passenger minivan “moves one passenger 180 miles on one gallon of gas.” So I see your point.
If you are so stupid as to apply the concept of moving a single vehicle a certain distance using a certain amount of fuel to the situation of moving a specified weight a certain distance using a certain amount of fuel, then you get whatever confusion you deserve.
A standard european spec semi can haul around 25 tons of cargo. I remember from an ad that the fuel consumption of a fully loaded Mercedes Actros is 18 litres per 100km (on level road, doing a steady 90km/h). That translates to 13mpg.
So if my math is right that means a truck can haul a ton of freight for 13*25 = 325 miles on a gallon of fuel (over favorable conditions).
Metric tons (100kG =~2200 lb) or US tons (2000 lbs) ? If metric, then the specific fuel consumption comparison is even better (by around 10%) than you calculated.
Small all-electric passenger trains (connected to a third rail or overhead wire) can employ regen-braking by dumping energy back into the power lines, but the big freight-hauling trains are almost always diesel-electric (a diesel engine drives a generator which drives electric motors at the wheels), and employ electro-resistive braking: this means the power gets dumped into a big bank of heating elements cooled by a fan.
It would take an absolutely massive bank of batteries to absorb the kinetic energy of a 15,000-ton train moving at 60 MPH (think “10,000 Toyota Priuses”).
The difference is that Honda minivans don’t average anywhere near 8 passengers. CSX is apparently reporting the actual annual average ton-mile fuel efficiency they achieve. They are not giving some theoretical figure based on best-case possibilities.
IOW, their advertising is accurate. It is not completely proof against attempts to parse it in strange ways - but that would be asking a lot.
Right, but I was assuming that common termini would have catenaries installed for this purpose. Diesel-electric locomotives can hook up to catenaries when available; they just don’t need to.
And I wouldn’t call the marketing for this deceptive at all: The truth of the matter is that, under the most practical way of comparing efficiencies, trains do much better than cars, and that’s also the impression that people get from the ads. It’s not CSX’s fault that the most practical way of comparing efficiencies isn’t the first way that people think of.
Not so much. Modern locomotives employ dynamic braking. In fact, if locomotives used solely the method you suggest, their motors would burn out in extremely short order.
