The Physics Of Hyperloop & Bullet Trains – Maglev

Bullet train

The bullet train isn’t a train at all. It doesn’t have an engine or wheels or a steering. It works on the principle of magnetic levitation(maglev) and magnetically guided steering. It runs at 330 Km/H, and was developed to overcome the energy lost in conventional trains via friction at the wheels.


The maglev tracks and trains maintain a constant alternating magnetized state with the help of alternating currents. The magnetism floats the train above the surface of the track removing friction. The train is then propelled by the track itself, which magnetically attracts it forward. Here’s a video that explains better than words:-

Hyperloop One: A Prototype

The Hyperloop is a brand-new mode of transportation proposed by Elon Musk. It uses the principle of pneumatic tubes and maglev to transport passenger pods through tube tracks between cities. The catch? They’re faster than airplanes! That’s right. With the right amount of engineering hours, Elon Musk projects to achieve a speed of more than 1100 Km/H, where as a commercial plane flies at around 900 Km/H.


Pneumatic tubes create suction pull by using large fans that push out air from inside the tube creating a near vacuum that pushes the container through the tube. The fan pulls out the air from the tube and pushes it out through the vent. This along with a complex computerized system handling all the whereabouts of the containers creates an efficient system which is used to transfer small things in a matter of seconds within a large building or a city.

The hyperloop works similarly, but in a much technically superior manner. In the hyperloop, as the pod moves forward, it compresses the air left in the near-vacuum state of the tube, thus slowing it down. To overcome this, it has a frontal fan that takes that air and vents it out the tube, maintaining a constant extremely low air pressure in front of the pod so that the air in front doesn’t compress to slow down the pod.

The hyperloop pod also uses maglev technology to remove friction. The propulsion system is pretty similar to that of a bullet train as well. The only difference that makes hyperloop faster is the absence of air inside the tube, which makes it maintain it’s speed like it was in outer space, at a minimal energy requirement used only to accelerate the pod.

Economics (Estimates)

  Cost of Construction Cost to Consumer Per Ride Speed
Bullet Train $17B ₹8000 – ₹10000 330 Km/H
Hyperloop $20B ₹4000 – ₹5000 1100 Km/H

Power Considerations

While the hyperloop claims that it is extremely energy efficient, there are several other energy requirements such as those of maintaining a near vacuum inside miles of tubing by running several air pumps. Yet it is believed to be better than bullet trains because bullet trains need a lot of power to maintain their speeds against the air drag throughout the track, which requires oodles of energy, thereby raising their costs to both the government and the consumers. Musk’s vision is that of a completely solar powered Hyperloop, however there remain several engineering constraints before him.

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