Shinkansen Bullet Train : The Incredible Technology of Japan

 


Today we’re going to talk about the Japanese bullet train Shinkansen, the fastest train in the world since 1964.  They are operated by Japan Railways (JR) Group companies and some of the fastest trains in the world, traveling at up to 325 kilometers per hour. They are famous for speedpunctualitycomfort and safety


Shinkansen
Photo Credit: JapanStation.com


Initially, these trains ran at up to 200km/h, which increased with improvements in infrastructure, and maintenance. What makes a bullet train, a bullet train-  I found five Technical factors  so, here we’ll talk about technical factors.   
Technically speaking for example – take a normal train and make five changes to it, you will end up with a bullet train. Of course, technically speaking, that’s true! 
Because when you implement technology in a different context and different culture with different people, the results are always different. So bear in mind that difference. So, the five technical factors. First! 

Number 1 Factor: Engine/Motor Location



A bullet train usually has about 16 compartments or carriages or cars.  On either side – the driver’s compartment; and in between, you have 14 compartments.
 

Where do you think is the engine of the bullet train? Is it in the front?   Or is it in the back driving compartment? Or is it somewhere in between? 


The answer is: it’s neither in the front nor in the back nor in the middle. Each of the compartments of the train has THEIR OWN MOTORS. So each compartment has two motors. And that is 28 different motors. 






So, it’s not the same as your everyday train where you have only one compartment or one engine, either the front or in the back. 


In the case of the bullet train, every single car, every single carriage compartment, is in itself has a motor that drives the car. So, that’s difference number one. 


But why? Well,  because what we are talking about here is SPEEEEED! and how do you make a train go at an extremely high speed? You give each car its own power. 


Each car, with its two motors, pulls at the same time. By adjusting their timing – synchronizing the motors together- you can have a lot of force to drive these heavy carriages together. 


At the same time, it also makes it very easy (comparably) to stop.  Because then, you apply brakes on all these 28 motors. And if you do it with synchronization,  you can stop much more efficiently without disturbing the passengers. Because each passenger experiences the braking of only their carriage.

 

Number 2 Factor: Wheel Shape


Let’s focus on wheels. Now, the shape of the wheel is very very important.  Well, if you have a flat wheel, what happens is, when you’re turning, it’s not able to turn very properly. 


So what’s the alternative to a flat wheel? You have the wheels a little bit conical in shape. It helps the train not derail, but the wheels move a little side to side as well. 


So,  they do not only go straight but also there’s a little oscillation, there’s a little movement from side to side. So, the wheels are not going straight. Rather they’re going straight like this.

Shinkansen and Normal Train Wheel
Conical and Flat Wheel




When you have a very high-powered train going with this kind of movement along the straight rails, they end up making the rails dysfunctional. They change the shapes of the rails and make them dysfunctional. 


This phenomenon had been observed many times in the past and this effect is called the Hunting problem. And the faster you go, the more observable is the Hunting Effect


Now when the engineers were thinking about driving the trains at speeds of  300 plus kilometers an hour, of course, they knew that hunting will become a problem. So what did they do? 


Japanese engineers came to a compromise. They didn’t want the wheels to be very flat;  they didn’t want it to be angled as much as it is in a normal train. 


So this shape, if you look at it, is not very much angled (not as angled as a normal train) but it’s also not the flattest wheel out there. So that’s the second difference. 



The Third Factor: Airbags for Sharp Curves



Trains sometimes take very strong curves. Sometimes the trains have to do that. And in case the train is going at a high speed of 300 kilometers an hour; if you have to take a  sharp curve for whatever reason, you are risking derailment. 


And that’s dangerous! And this is what we call the Banking Problem. So, what do you do? Now if you have observed a motorcycle racer, you will notice that when they are taking sharp turns, they also turn their body TOWARDS the curve.




Bikers towards curve
Photo Credit: Google Pics





Now on a bullet train, when the train would take a curve (a sharp curve), you risk a lot of discomfort to the passengers who have paid a lot of money to enjoy the ride. So what do you do?   


In each compartment, you have an airbag. And this airbag is full of air; but how much air goes what way is controlled by a computer. So a system (a computer system) controls it.  


Hence, making it easy to bank without discomforting the passengers. So, that’s the third big difference! Without compromising the speed they found this amazing solution to make banking as easy as possible. 



The Fourth Factor:  3000% Sturdier Pantograph



All of the electric vehicles that you encounter in your everyday life  Metro trains, Subways,  Trams- all have a pantograph. It transfers the power from the wires (electrical wires) up there, onto the motor of the train. 


But there’s a difference between the way the bullet trains have built their Pantographs and the normal pantographs (that you have in normal trains). 


You might have observed that sometimes when the trains are going at a very high speed, you can see the pantographs creating some sparks on the wires. 





Sparking Pantograph





Why do we have these sparks? What happens is that the pantograph is not always able to make continuous contact with the wires up there. So, sometimes because of the air, the wind, the speed of the train, and other factors. 
What happens is that sometimes there is a small disconnection between the pantograph and the electrical wires. And so,  this small gap in the contact, what it does is the air in that gap becomes plasma. And plasma as you know is a very high-temperature thing. 
It ionizes the air in that area!  This plasma spark can create big problems when you’re driving the train at 300 kilometers an hour. It doesn’t create much problem in trains that drive at let’s say 40 to 50 kilometers an hour, which is the case with the metros and the subways and the trams. 
But at high speeds, the stakes also are very very high. And so, THAT becomes a problem. So what do we do so that there’s never a breakage in the connection? 
There’s no discontinuity; the pantograph never breaks away from the wires up there?!! So, what the engineers came up with was a compensation mechanism – a   feedback system – a kind of a lever system.
 

Shinkansen Pantograph
                                    Shinkansen Pantograph                                      Credit: Google Images



You can avoid this planarization by changing the air into plasma – these sparks which can be lethal, which can be potentially very very dangerous- you can avoid these dangerous (potentially dangerous) plasma sparks by making the pantograph never leave the electrical wires. 


And that’s exactly what the engineers did. They supplied a feedback mechanism. So, a spring system works here. And so, what happens is that the pantograph always PULLS UP.  


It applies an upward force to the electrical wires. And if the electrical wires for whatever reason – wind or speed or any other reason- if the electrical wires try to push down on the pantograph doesn’t resist it. 


Actually, it just pushes down because of the way it is constructed. And you’ll be surprised to know there are 25,000 volts of electricity flowing down these pantographs to the electrical motors. So that’s a lot of voltage. 


On a normal train, the electrical supply is about 800 volts. It varies between 700 volts and 1000 volts, but let’s take an average of 800 volts. Even at 800 volts, you can see these plasma sparks on the pantograph and the wire connection. 


Now, imagine the quantity, the amount of ionization of air when the pantograph,  instead of supplying 800 volts, it’s supplying 25,000 volts. That is how much bigger – 30 times.


So, 30 times bigger voltage can create at least 30 times bigger plasma sparks and these plasma sparks (30 times bigger plasma sparks) would be big enough to destroy the electrical wires.  

And they increase the chance of the train compartments catching fire. So that is very very dangerous. So at 25,000 volts, with the train running at 300 km an hour, you can’t afford even a microsecond of disconnection between the pantograph and the electrical wires up there. 
So that’s why they needed a system, a pantograph -we can say the perfect pantograph. And they did it! They built it using their ingenuity! n that’s the fourth big difference between a   normal electrical vehicle (electrical train) and a bullet train. 




The Fifth Factor: Biomimicry from Kingfisher Beak



So if you look at the front of a normal train you see a boxy thing but the front of a bullet train, as you can see here, it’s not a box. Now, this shape is very unique.
But the question arises why do we need this shape? If you look at the first bullet trains that were unveiled in 1964,  their front actually looked like a proper bullet like a gun bullet.   
But very soon engineers realized a big problem. So what happened is, as you know Japan is a very mountainous country. And so when they built these bullet train tracks, they have to cut through a   lot of mountains. 
So, the bullet trains would go through a lot of tunnels. Now, what’s the problem there? Well, the problem is with the design that we had initially in 1964, it didn’t allow the air (to escape). 
Because when you’re going inside the tunnel at 300 kilometers an hour what happens is the air that was in the tunnel has no way to escape because of the shape of the bullet train. And so, the air is also pushed at a very very high speed. 
 
What it does is it creates a SONIC BOOM (a sonic blast). So, as soon as the train enters one end of the tunnel,  the other side of the tunnel would ooze out a lot of very dangerous waves coming out at a  very dangerous speed. 
So this sonic boom -this sonic disturbance was extremely dangerous;   and engineers had to do something about it. 
So they realized that the best shape to cut through the air without creating this sonic problem is to make the face of the train similar to the beak of a Kingfisher. 
The kingfisher’s beak is very unique and it allows for the optimum breaking of the air or water in a very streamlined way. And that’s exactly what the engineers wanted for the trains to do. 
Biomimicry from Kingfisher Beak
Credit: Google images

They wanted the trains to break (the air), pierce through the air, allowing them to escape not only in the front but also in the back. 
And so, when you see the front of a bullet train,  there’s the beak of a kingfisher. So, these are the five technical differences between a normal electric train and a bullet train.
Five technical difference

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