Update: This article was originally published the morning of July 26, 2019. After publication, a Ford spokesperson contacted Road & Track to provide further context regarding the stunt, which has been added below. Additionally, a new Engineering Explained video published on July 31st has been added to this article.

We’ve seen a Toyota Tundra tow a Space Shuttle, a Tesla Model X haul a 787 Dreamliner, and now we have the joy of witnessing an electric Ford F-150 prototype chugging along towing 1,250,000 pounds of train behind it. Is it cool? Obviously! Does it matter? Of course not.



In the video, a prototype EV F-150 first tows a bunch of empty train cars, adding up to a million pounds. Then, the crew loads the empty train cars with a whole slew of new production F-150s, 1.25 million pounds in total, and the electric pickup gets the train rolling once again. Watch for yourself:

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Did the F-150 actually pull 1.25 million pounds? Yes. Is this a legitimate competitive advantage? No. This is just another clever marketing illusion, where what’s accomplished is far less of a feat than the initial appearance implies. Plenty of vehicles out there could do the same—but you have to give credit to Ford for the innovative spectacle.



What’s the catch? Well, the Space Shuttle and 787 both rode on rubber tires, and those towing feats were conducted on paved surfaces. Ford's stunt involved a much heavier load, but it was resting on steel wheels riding on steel railroad tracks. This makes all the difference. Why? Ultimately, it's a matter of the coefficient of rolling resistance, the ratio of the force required to pull a rotational mass.

Let’s imagine we have a 100-pound rubber ball sitting in a pile of loose sand. Say the coefficient of rolling resistance is 0.3. If we tie a string to that ball, it would take a 30-pound force to move it (F = Crr*N = 0.3*100 = 30 lbf). Now if we take that same ball and place it on concrete—a much firmer surface—suddenly our coefficient of rolling resistance decreases to about 0.01. Now it only takes a one-pound force to move it, 30 times less than what was required on sand. As you move towards materials that have less deformation, you decrease the force required to pull an object.



Steel does not deform much at all, which is why railroads use steel wheels on steel tracks. This adds up to an extremely low coefficient of rolling resistance—about 0.0015. To pull a 10,000-pound train across a level surface, you only need a 15-pound force. For a truck to move a 1.25-million-pound train, it only requires about 1875 pounds of force.



Can a light-duty pickup truck pull with 1875 pounds of force? Absolutely. Generally speaking, the maximum force a 4WD truck can generate will be equivalent to its weight. This is due to the tires, which can only grip so much. In a tug-of-war battle between two 4WD trucks, as long as both vehicles have decent wheel torque, the heavier truck will always win. We don’t know precisely how much the electric F-150 weighs, but it’s safe to assume it’s at least as heavy as a 5000-pound four-door F-150 in production trim. Five thousand is significantly greater than 1875, and thus the Ford pulls the train, no problem.

The bad news? Take that same 1.25-million-pound train and put it on pneumatic tires and pavement, and Ford’s stunt falls flat. A tire on asphalt has a coefficient of rolling resistance that's roughly 10 times greater than that of a steel wheel on a steel rail. The electric motors of the 5000-pound F-150 could whine all they’d like—there just wouldn't be enough mass in the truck to give it enough traction to generate the 18,750-pound force required. The pickup might spin its tires to oblivion, but it wouldn't move an inch.

Using a pickup truck to pull 1.25 million pounds on a railway sounds impossible. In reality, the railway is exactly what makes it possible. Ford's stunt was a fun spectacle, but you could probably achieve the same thing with the typical all-wheel drive family crossover.

Update: A Ford spokesperson contacted R&T to point out that our calculation did not evaluate acceleration. That's true, and it's due to the fact that Ford's video did not give any indication of how quickly the truck-and-train combination accelerated during this demonstration. Remember, force is different from power, and power is a measure of work done over time. We can (and did) calculate the amount of force the truck exerted (in pounds) to get the train moving. But without knowing how much time it took to reach a certain speed, we have no way of calculating the amount of power (i.e., horsepower) it took to move the train.

Here's another explanation, courtesy of the internet's favorite whiteboard:

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