Lately, this peculiar little single wheel monorail came to our attention. Built by [extraglide1976], all from Meccano. His build started with modest tests: one gyro obviously flopped. Two gyros geared together ran slightly better. But when he adds active gimbal control, things suddenly come to life – the model shudders, catches itself, and carries on. The final green-roofed locomotive, with LEDs signalling ‘system go’, trundles smoothly along a single rail on [extraglide1976]’s deck.
To be fair, it houses a lot of mechanics and engineering which we don’t find in the monorails of today. We do have quite a few monorails in our world, but none of them balance on a single wheel like this one. So, where did this invention derail?
Outside of theme parks, Japan is one of the few countries where monorails are still used as serious urban transport: though Germany’s century-old Wuppertal Schwebebahn, the lesser-known C-Bahn, China’s sprawling Chongqing and Shanghai systems, Malaysia’s Kuala Lumpur line, Brazil’s São Paulo network, the US links in Seattle and Las Vegas, and India’s Mumbai Monorail prove the idea has quietly taken root elsewhere.
The thing you’ll see in nearly all these monorails is how the carriages are designed to clamp onto the tracks. This is of course the most safe option, but it loses out on speed to the ones that sit on top of the tracks, balancing on one wheel. Such a train was actually invented, in 1910, by Louis Brennan. His original monorail promised faster, cheaper transport, even using existing rails. The carriages leaned into turns like a motorbike, without any intervention from the driver. Two counter-rotating gyroscopes kept the carriage upright, cancelling precession forces like a mechanical Jedi trick.
Back then, it failed commercially, but today? With cheap sensors, brushless motors, and microcontrollers, and intelligent software, why not let it make a comeback? It could carry freight through narrow urban tunnels. With high-speed single-rail pods?
Investors killed Brennan’s idea, but we live in a different time now. You could start out with a gimmicky ‘snacks and beer’ highline from your fridge to your garage. Share your take on it in the comments!
this has 4 wheels, so not a single wheel monorail.
“It could carry freight”
The problem with gyrostabilization is that the greater the vehicle mass the more mass is required in the gyroscopes to generate the stabilizing force necessary to keep from tipping. Lit motors C1 only had a gross vehicle weight of 800 pounds but required two 20 pound gyros. The 1967 Gyro X 1,850 pounds but needed a 20 inch diameter 267 pound gyro rotor. A single fully loaded freight car can weigh up to 315,000 pounds, or about 157.5 tons. Can you imagine the gyro that would require? The fuel wasted spinning it? The destruction it would wreak in a catastrophic failure? I cant imagine the benefits outweighing the hazards.
Or about 142,881 metric tons.
I don’t think urban environments where you’d have a monorail would call for the kind of freight car you’re referring to. We’re more talking about delivering toothbrushes to pharmacies than iron ore to smelters.
I’m rather surprised there was no link to this earlier HaD article on the Brennan monorail.
https://hackaday.com/2024/01/31/the-gyro-monorail-how-to-make-trains-better-with-a-gyroscope/
The Yellow and Pink line in Bangkok, Thailand come to mind.
ok, why using it?
it is faster, or cheaper? no!
I’m not defending the idea, which seems impractical to me. But yes, the claim is that this can run significantly faster than a normal train or monorail. Normal rail cars have to slow down around curves to avoid tipping. This design simply “leans” into the curve without slowing, like a motorcycle.
And yes, faster trains can be “cheaper” since you don’t need to buy as many to service the same number of daily riders.
And having only one rail is cheaper to install and is less intrusive in an already existing city environment.
The big problem is that it crashes as soon as it loses active control. Any power glitch or software issue and you’ve killed people.
Regular trains slow to a stop and stay on their tracks in the event of a power outage.
The same is true of hovertrains (which were the subject of experimentation from the FIfties to the Seventies) and mag-lev trains (still popular today). Mister Musk’s Hyperloop is even worse, as even if the train stops safely you are stuck in a tube with an unbreathably thin atmosphere.
Most maglev systems aren’t designed to levitate at very low speeds or while stopped. In these situations, wheels are deployed for taxiing, braking, and parking at stations. In case of a power outage or a malfunction in the levitation system, these backup rollers or wheels are crucial.
The Transrapid has sled strips (a wear item) on the underside to slide on in the event of a levitation failure. Also, I beleive that in the event of a power failure the spools could generate electricity to at least allow it to float until it slowed down to moderate speeds.
Why would you assume falling from the rail is fatal? You could build in a catch system to save the train if it starts falling for whatever reason. Just like an elevator doesn’t drop people to their deaths if the main winch fails.
Not really – loosing power might eventually make it fall over, but the gyro’s will have so much inertia it will want to stay on the rails and upright enough for a good long while – you have lost the active fine tuning of its balance, not removed all the passive stabilisation. So with no drive, and likely automatically applied brakes it will be slowing down.
Making it a race between the flywheels running out of adequate passive stability and the system as a whole slowing down – for the sort of relatively slow urban situations a monorail might make sense for I’d bet you are not killing people any more often than the bus/tram/car/motorbike when the driver or vehicle has an issue in similar situations. And with no power it likely would also be automatically deploying stabilising wheels or a kickstand/skid too – it won’t fall over, maybe it leaves a scratch in the road surface and settles at a slightly wonky angle, but it isn’t going to come flying off the rails..
Nothing is risk free, but inherently this concept could be done safely as long as the operational window stays within reasonable limits.
Germans have a word for this. “Gadgetbahn”.
Fun as an experiment and possibly for themeparks and very niche applications, but with no advantages over already existing solutions that are not by far outweighed by it’s disadvantages.
We also use “Elektroscheißwurst” to describe those slow commuter EMUs blocking the railway which should be used only by high speed trains.
I’d be a lot more impressed if the track had curves.
As a demonstration of the principals of self- balancing using gyroscopes, this is fantastic. I challenge anyone here to build a self-balancing vehicle using a gyroscope – it ain’t easy.
principles
“Single wheel” is comically wrong when applied to this thing which is clearly a “single rail”, maybe a “single track” design but nowhere near “single wheel”. Other than that, I find the concept comically unsuited for real-world applications. One of the first things one should ask oneself is: how much extra strain is put onto the single rail that has to do the load-bearing work of two rails in the conventional design? How much weight for gyros is necessary per car (!!) to obtain about the same stability as with the conventional design? How to ensure that the train doesn’t just topple in case of power failure or the complicated mechanism breaking otherwise? How would a train with several cars behave should one car loose stabilization? What is the mechanism to hold the car straight when powering it down? Can powering down happen at all stations, can it happen midway, like, anywhere? How much energy is wasted to keep something upright that really really wants to topple all of the time? Would it be possible to operate more similar to a bicycle when running at speed, thus using the wheels to provide (additional) stabilization? Can it be made to run as safely at speed on a single rail as the conventional design does on two rails? In conventional trains, one can simply put a passive car with no electronics, no motor onto the tracks where it can be kept indeterminately until being picked up, and practical cars can be as simple as a platform with two axles and four wheels. It’s a lot more effort with a balancing monorail.
If you can find a way to make the gyroscopes powered by AI then funding will become no problem.
Hah that would be funny, take something which requires at most a simple PID controller and hand it to an LLM for absolutely no reason so it hallucinates and takes out a whole neighborhood with an industrial spill. But the investors will be happy
Jfc….. No.
Hell no. Why would you want a wacky unicycle freight train which flops over on its side if it has a power failure? Do you trust the people around you to maintain that correctly?
Very very cool, but…
Catenaries can be used with regular trains, but not with monorail trains.
Monorail trains must lean into crosswinds, while regular trains basically ignore them.
Wind gusts can make monorail passengers motion sick.
A catenary system can be used with a tippy monorail – it just makes the pickup on the monorail cart a more odd round shape to roughly match the motion at the top, and likely increases the speed wear forces you to change or at least rotate that contact to a fresh spot. Not impossible though it certainly comes with added challenges.