Say Hello To The Floating Trains of the Future
As an inquisitive child growing up, I am mostly fascinated by the small magnet beside my mother's sewing machine. The magnets usually have all types of needles on it. You may agree with me that magnets are fun to play with, but they have many other uses beyond that.
Part of its use is in magnetic levitation (maglev), which finds application in high-speed travel innovation such as high-speed magnetic trains.
[Wikipedia Creative Common Image]Source: A maglev train coming out of the Pudong International Airport in Shanghai
For instance, in 2004, the first commercial high-speed maglev train, Shanghai maglev train, opened up her doors for business and was able to reach a high speed of 431 kilometres per hour or 267 miles per hour. This speed far outstrips the rate of American's Amtrak Train, the fastest high-speed commuter train, which only top speed is 241 kilometres per hour (150 mph).
One of the big challenges of high speed rail transport is the problems of wear and overheating due to friction between rail and bearings.
This challenge is what the maglev train tries to fix. A train that is levitated do not bother about wear or overheating as a result of friction. The only resistance that the train could encounter will be air resistance. This makes the maglev train to move very fast.
The maglev train as we have it today may be something new, but the basic principles of the technology were one that is known for decades dating back to the First World War.
How it works
Maglev trains are mainly about magnetics. From the elementary science, we all know that magnetics comprises of two poles: the north and the south.
[Wikipedia Creative Commons]Image by Pieter Kuiper: Magnetic like poles repel
The like poles (N-N or S-S) repels, and that is the basis of levitation in maglev trains.
The Japenese Rail Pass Company (JR Group) uses this magnetic repulsion to generate lift which lifts the train off the tracks.
Magnet with similar poles is on both the train and the track. This repulsive force creates an invisible, almost magical, cushion which the train rests on.
This method used by the Japanese maglev train engineers are known as the electrodynamic suspension (EDS).
While the Japanese system is based on the repelling force of the magnet, for the German system, the engineers use the magnetic force of attraction (unlike magnetic poles attract). The system is known as the electromagnetic suspension (EMS).
You can make a homemade electromagnet using either an AA or 9V battery. All that is required is a battery, a copper wire, one nail or screw and a metallic object which you can attract; in this example a small nail.
Wind the copper around the nail, connect one end of the wire to the positive terminal of the battery and the other end to the negative terminal of the cell. You now have an electromagnet that will attract the small nail when the connection is active. Once you disconnect the copper wire from either or both the battery terminals, the magnetism fails. You can watch a video of the process here.
The Germans made use of this principle. But the train will be useless if the track and train attract each other since they will stick together-just like in the homemade experiment above when the copper wires are connected, and the nail was attracted.
The trick was to use the same electromagnetic property to achieve levitation in another style.
The electromagnets attract when current is switched on and loses magnetism when switched off. If you can switch on and off very quickly, the train will be lifted and "dropped" back to the track. But because the switching is high-speed, it will neither drop or attract each other but will hover in the air. That is how the levitation is achieved by the German system of Electromagnetic Suspension (EMS).
Although both the EDS and EMS work on the same principle using magnetism to achieve levitation and propulsion, there are some differences in both features. These differences, advantages and disadvantages are listed in the table below.
Electrodynamic Suspension (EDS)- Japanese System | Electromagnetic Suspension (EMS)- German System |
---|---|
Levitates to about 10cm | Levitates to about 1 cm |
Train starts off on rubber wheels before attaining liftoff speed at about 100kph (62 mph) | No wheels here as train lifts off as soon as the guideways are energised |
The engineers argue that the wheels are a safety feature too in the event power fails | German engineers said they have emergency battery pack so when power fails the train does not have to drop back on the track at top speed |
Faster due to more margin between train and track. Fastest speed recorded is 603km/h or 375 mph | Highest speed recorded is 500 km/h or 310 mph |
How Propulsion is Achieved
We have seen how the train achieves its levitation, what is next is how it propels (move) forward.
The north pole of the track magnet attracts the south pole on the train magnet. On the other hand, the south-pole of the magnet on the track repels the south-pole of the magnet on the train.
The polarity of the magnet on the track changes immediately the attraction and repulsion occur pushing the train forward. Meanwhile, the polarity of the magnet on the train never changes.
The coils in the track create a magnetic field through the pushing and pulling forces which hold the train in position.
An extremely strong magnetic is required to lift and move the train at such high speeds.
For that to occur, a superconducting magnets are made. To make a conductor have extremely low resistance the temperature of it has to be brought down very low. The Linear High-Speed Train has the temperature cooled to -269ºC.
The conventional magnets could barely lift a train 1 cm off the ground. But superconductive magnets are capable of producing the magnetic force capable of speeds of 580km/h in just 8.8 kilometres.
Advantages of Maglev
- The only friction here is the friction between train and air. The other problems of friction such as overheating, wear and tear are reduced drastically leading to large scale savings in cost.
- Time of transportation between one point to another is now small. The distance between Tokyo and Osaka is 503 kilometres, conventional Japanese high-speed bullet trains or Shinkansen using the Nozomi(train) will take 2 hours 30 minutes to reach there while travelling at 186 mph or 300km/h. By 2045 the Japenese plan to have a maglev track rail to Osaka to reduce the time to 1 hour while travelling at 500 kilometres per hour or 310 mph.
- There is reduced CO2 emission if the source of power is green.
"In addition, the amount of CO2 emissions that the superconducting maglev produces when carrying one person between Tokyo and Osaka is approximately one-third that of airplanes," the company said in a statement. Source
4. There is increased safety on use of maglev as it has been proposed to function during an earthquake since it levitates. Building engineers even want to leverage the technology to build homes more resilient to earthquake.
Everything that has an advantage will have a disadvantage if you look close enough.
Here are some of the disadvantages of the maglev
Disadavtages
- Cost: The elevated Shanghai Maglev train costs a whopping sum of about $1.58 billion USD for a length of 30.5 kilometres. That translates to a cost per kilometre of the track to be approximately USD 50m which includes the cost of trains and stations.
In 2008 an Australian Transrapid conventional bullet train costs $34 million AUD for the dual track. That makes the Shanghai Maglev almost twice as expensive as the high-speed train. - The magnetic fields from the superconducting magnets may disrupt the workings of a pacemaker. Hence the need to shield passengers with a pacemaker. A pacemaker is a device that helps stimulate and regulate the heart muscle and its contraction. A strong magnetic field could affect its working leading to a fatal result to the wearer.
While we are talking about the high speed of the maglev trains, some are already looking into the future with the vacuum train or vactrain. That is a train that will run in a vacuum. Without air resistance, some believe achieving a speed of 4000 km/hr is possible. The future will be an interesting one for both travel and technology. Can we have such technology or could it be just another pipedream?
Thank you for reading.
References
- The Basics of Magnetic Levitated Trains (Maglev)
- Wikipedia: Maglev
- Japan's Maglev Trains
- Long Distance Maglev Plan by Japan
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Hahahah pipedream, I see what you did there lol.
Oyibo bu agbara! Maglev is some very cool tech and now they want to create vaccum trains so they can eliminate even the wind resistance?! Chai! 🙆. Oyibo bu agbara!
I can't help wondering how a vacuum train would work 🤔
For instance, for it to run on the surface you would have to have like a transparent airtight tunnel of some kind made of some form of really hard glass or really hard plastic or some transparent metamaterial or whatever. In order to accommodate the airlocks for passengers to safely board and disembark, it would have to be quite wider than the train itself. You need some way to guarantee that if the vacuum envelope gets punctured that the pressure differential will equalize slow enough not to kill everyone.
If it's underground, then you might need to have the whole rail system of tunnels and stations under vacuum conditions (I'm imagining repair workers in spacesuits crawling through cathedral-sized tunnels haha) If not, then just the tracks.
Oh and in either case, the train has to have its own contained air supply or some means of safely acquiring air from outside without breaching the vacuum.
Great post, very informative.
I have always loved technology. Might still go back to get a B.SC in it. It fascinates the mind and all you need to do is think of it, then you can achieve it. Though we dont have one in our country, the technology behind the maglev train looks simple enough.
Quick question though, is the magnetic force generated from actual magnets or electromagnets? If it is an electromagnet, I have an idea why it might not work in my country :). Good write up!
The more the merrier :)
It will work anywhere provided our government will agree to spend money on such things. Then they'd have to improve power availability too as it requires it to run.
As informative as usual @greenrun. Am sure a lot more technology will soon make this one a thing of the past. Is Vactrain same as hyperloop which I read last year Elom Musk is working on?
They are very similar technology. Thank you.
@Greenrun running the magnetic trail this time around. This is quite futuristic but I believe it will find application soon enough in daily life once they can figure out a way to make it cheaper.
My question is:
Since this maglev works on the priniciple of magnetic repulsion, won't the train be repelled off the tracks?
Keep slaying bro! Cheers!
No, it won't be repelled off the track. The two opposing force of attraction and repulsion keeps it forever hovering. Thanks for dropping by. We appreciate it :)
Reading this, i had the same question in mind. i know it wont be repelled off track. but with the much time i've spent playing with magnets, i've realized that it gets pretty tough keeping one magnet hovering over the other by repulsion. there is always that tendency to wanna skid off and get attached to the side.
question...is there something i'm missing?
However, i feel that a possible solution to that would be increase in surface area of both magnets. that way, it doesnt skid off to one side when on high speed. i could be wrong though.
Neat write-in bro. as always
@pangoli, I was expecting you to ask how it turns..check the image here, you will see the levitation coils are facing each other which is found under the guardway (rail track name for the maglev). The superconducting magnet made up of these coils produces a repulsive force. Each coil repels the other. That maintains the train in the centre at all time.
Wait o, who's the 'We'
@fejiro, the Greensville Family :)
HELP!!!!
does it make me attractive...
if I swallow magnets ....
I have never really tried that, but now that you mentioned it, I may just do that to see how deep the rabbit hole is :)
The fact that it levitates ..it is really cool...Trains have always been somewhat the safest means of transportation..speed was the disadvantage but now that we have fast trains....it is way cool.. Thanks for sharing
I think rail is still a very safe means of transportation. Thanks
Magnets were all the fascinations we had during our childhood, never diminishing memories they are..And amazingly you connected it with the technology..It is also the fastest moving commercial train and train takes only 30 mins for journey..Amazing it is
It is very fast when compared to the conventional trains.
Messed around with this back in secondary school. I almost felt like an inventor :), an Isaac Newton blessed with magical powers.
I hope trains as described in your post can be implemented here in Nigeria, fast trains would really cut down on transport costs, less accidents too. And the issue of traffic congestion would greatly reduce.
But then it's all hopes.
PS:
The formatting in this post is super lit. Where did you learn such markdown gymnastics? :)
It will work here at double the operating cost due to our current history of epileptic power supply. But I'd pick the train over the "luxury" buses we currently operate on. Thank you.
About the markdown, just learned from reading. There's nothing spectacular about it. Do keep steeming.
i am a mechanical engineer ,i am impressed your(country)technology,,
thank you for post.
@mafi001, this is not my country's technology. Thank you.
Is this even possible ? I am sure that the Maglev would make use of two superconducting magnests Luke you said and one would be lcaed on the ground while the other on the train. In the eventuality of an earthquake, there possibly would be a shift or change of orientation of the superconducting magnet placed on the ground which would make the moment of the train impossible ...well what do I know.? Just my opinion though.
I'd still prefer to float than be on the ground in the event of an earthquake. Thank you.