Talk:Gyro monorail

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[edit] Maglev

Not as 'sexy' as maglev, yet still sufficient to affront the establishment as a challenge to their monopoly of wisdom and expert status, the gyro monorail has never had a favourable press. Most assessments reflect the ignorance of the authors, rather than real deficiencies, conclusions appear to be written before the analysis, baselines for comparison are conspicuous by their absence, or ill-defined, Intuition is in evidence where objective analysis and sound scholarship are required. I thought it high time some facts were introduced to the debate. Gordon Vigurs 11:30, 19 March 2006 (UTC)

[edit] Language

What are you talking about? This is the English language Wikipedia. There's nothing stopping you front translating it into the other languages for the other wiki's.SirLamer 15:42, 21 June 2006 (UTC)

[edit] Wow

Well, this article must be one of the most detailed, complicated, technical articles on Wikipedia, all wonderfully illustrated with incomprehensible diagrams and formulae - that tells me absolutely nothing about the most important question - does it work?? Can we have a section on real-life implementations and why they succeeded or failed? Thanks. DWaterson 23:51, 11 November 2006 (UTC)

[edit] I like this sentence:

Gyros work because sulum proprius of orbita quod est simultaneously spinning quod precessing insisto a trajectory per veneratio ut torpeo tractus quod est symmetrical super spin , quod precession axes , tamen asymmetrical super tertius axis , hinc adicio Newton’s Secundus Lex ut sulum proprius , quod consummatio pro universitas rota , illic est casses moment inter tertius axis. That’s it; there is nothing mystical or strange about it.

なるほど as they say in Japanese.

Like the guy who commented before me, I'd like some explanation as to why we're not all riding around in Gyro Monorails. There's a photo with the article, so someone must have built one at some point, but what happened to it? --61.214.155.14 05:44, 20 November 2006 (UTC)

[edit] If you insist

There are many technically sound ideas that never caught on, this is one of them. See Monorail history for what little history there is. The problem is that the only nations with the technological resources to develop it already had extensive conventional railway networks. It was an idea some 50 to 100 years ahead of its time. I'm sorry, but the article cannot be dumbed down further. Gordon Vigurs 17:58, 25 November 2006 (UTC)

Ahem. I hardly think that it is "dumbing down" to provide readers with useful, practical information. Wikipedia is, after all, an encyclopaedia, not a technical manual. You wouldn't expect to have, say, a technical article about how televisions work, without then saying what programmes you can watch on them, would you? DWaterson 21:29, 25 November 2006 (UTC)
Actually I would. The functioning of televisions has nothing whatsoever to do with the plots of soap operas. Also, it is doubtful whether the readership of one would be remotely interested in the other. Gordon Vigurs 23:01, 26 November 2006 (UTC)
Very well. I find that a rather pretentious and arrogant approach, but clearly you consider it appropriate for this article and I bow to your superior knowledge on the subject matter. Nevertheless, I think you will find that Wikipedia, as an encyclopaedia (not a technical manual) seeks to blend both practical and technical information in a manner that the layman would find useful. Therefore, I do still think that it is appropriate to include a section on the gyro monorail in practice in the article. DWaterson 02:19, 27 November 2006 (UTC)
I don't disagree, but the article is already very long. OK, I'll put an extended introduction in to cover history of development, examples etc.. Watch this space. Gordon Vigurs 08:48, 27 November 2006 (UTC)
I've added a section, which I hope covers the missing information. By the way, thanks for taking an interest. Gordon Vigurs 20:25, 27 November 2006 (UTC)

Thanks for the newly-added history background, I think it really improves the article. --220.106.63.163 03:05, 7 January 2007 (UTC)

[edit] Request to 'wikify'

Please specify precisely in which respect the article is deficient. It appears to conform to the manual of style, but the subject matter is not amenable to presentation as a geek list.Gordon Vigurs 11:44, 11 December 2006 (UTC)

The most obvious:
  • GIANT images (use "thumb" without a px size)
  • Images without captions
  • Title Capitalization Of Headers
  • Linking of notable terms to their articles
  • Unit formatting and metric conversions
— Omegatron 15:33, 11 December 2006 (UTC)

Thank you. Regarding image formatting, the layout guide and manual of style are not completely consistent, so as a newcomer I welcome advice. Gordon Vigurs 22:06, 11 December 2006 (UTC)

Note that thumb without a set px size leaves the image at the user's default size. If you want a bigger default size, you can set it in your user preferences. — Omegatron 14:59, 13 December 2006 (UTC)

[edit] Derailing

Intuitively, I would expect the gyro monorail to derail much more readily than a conventional twin-track train, given the same level of ground vibration. How did the designers prevent derailment, or did they just ignore the problem? --220.106.63.163 03:20, 7 January 2007 (UTC)

I'm not too sure that it is likely to be any worse, a double flange imposes a pretty extreme constraint on the lateral displacement of the wheel. Brennan's model quite happily negotiated a bridge consisting of a stretched cable, with no tendency to fall off. The radii of curves used in the test tracks were much sharper than could be negotiated by a conventional railway - again showing no tendency to derail.
During trials with the full size vehicle, Brennan deliberately spun the gyros in the same direction so that the actuation torques introduced a net yawing moment, introducing a tendency to derail, as well as the potential for instability described in the article. Again this caused no major problems. I suspect it is the erroneous assumption of pitch/yaw gyroscopic reactions on the vehicle which gives rise to this intuition. In a double counter-rotating gyro system, such as employed by Brennan and Scherl, these reactions are balanced out leaving only roll torques.
Please expand your point, it may well be valid. After all, nobody to date has driven one of these things faster than 30mph.Gordon Vigurs 16:58, 11 January 2007 (UTC)
Sorry for the slow response. I think Brennan's experiment defeats any amount of theoretical hand-waving on my part.
For the sake of completeness, I will try to explain better. I was thinking that since a conventional train not only has a flange on each wheel, it also has a stopper on each side, it is less likely to derail should the track suddenly move out of the way. --220.106.59.56 12:59, 26 January 2007 (UTC)


[edit] Rotation of the Earth

Gordon Vigurs,

I suggest that you insert remarks in the article about the effect on a gyroscope of the rotation of the earth. The gyroscope will keep pointing to the same spot in the sky, and as the earth rotates, the axis of the gyroscope will follow the point in the sky as it moves west.

A vehicle at the equator, pointing in a north south direction, and stabilised by a gyroscope spinning round a vertical axis, will tilt 15 degrees in an hour as the earth rotates, that is 360 degrees in 24 hours. The tilt will be 15 degrees every hour to the west as the earth rotates from west to east.

If the vehicle is pointing in an east west direction, the vehicle will try to pitch eastwards 15 degrees an hour, as the earth rotates. The rail will resist this pitching motion, and precessional force will convert this pitching force into a rolling force, so the vehicle will tilt to one side, 15 degrees in an hour. Contra rotating gyroscopes will try to precess to the south and north, so that the precessional forces will cancel and be absorbed by the structure of the vehicle.

If you hold a spinning bicycle wheel by the axle, you can feel and see the precessional forces as you force the wheel to change its orientation.

At one of the poles, if the vehicle is stabilised by a gyroscope spinning round a vertical axis, the axis of rotation is the same as that of the earth, so that the both the earth and the gyroscope point to the same spot in the sky, and the gyroscope will always keep the vehicle vertical.

At the equator, if the vehicle is pointing in an east west direction, and the gyroscope spins round an axis pointing north south, that is parallel to the wheel axles, the gyroscope will also always keep the vehicle vertical, because the axis of rotation of the gyroscope is parallel to the axis of rotation of the earth.

David Erskine —Preceding unsigned comment added by 58.168.40.76 (talk • contribs) 06:44, 21 September 2007

58.168.40.76 03:48, 27 September 2007 (UTC)

These are relevant comments and ought to be included, if only to discount the effect. Some comment under 'turning corners', as the comments about asymmetry as the root cause of instability refer to motion with respect to inertial space, but as you correctly point out, the vehicle is constrained to rotate with the Earth.
The behaviour you describe is of a gyro in an unconstrained gimbal, free to rotate with respect to the Earth, and assumes that zero torques are acting on it, which clearly is not the case. The degree to which this motion is observed when acting against the constraints imposed by the balancing system, depend on the relative magnitude of the torques associated with forced precession at the Earth's rate of rotation, compared with the actuation torques. These are tiny, so the unconstrained behaviour would be swamped by the action of the balancing system elements, and the gyro will maintain its orientation with respect to the vehicle regardless of latitude or duration of operation.
It is not valid to assess a closed loop system on the basis of open loop behaviour. If the gyros were free to move to the extent that they could align themselves with the Earth's rotation, the balancing loop would be too feeble to remain upright.
Where this effect (the alignment of a free gyro with the Earth's axis of rotation) is used in practice, i,e, the gyrocompass, extremely high quality bearings are required to stop it from being swamped by friction, and every effort is made to avoid constraining the gyro motion.
The Earth's rotation (or more correctly, the pitch and yaw motion of the vehicle with respect to inertial space arising from its resting on the Earth) produce small disturbing roll torques. The roll constraint does not apply because the vehicle may roll freely with respect to the Earth. These are no different as far as the operation of the balance loop is concerned as any other roll disturbance, such as much more significant effects like cross winds and lateral payload shift; the vehicle will lean very slightly more or less than would be predicted from a non-rotating Earth. The increase in roll angle is calculable by equating the toppling moment with the gyroscopic torque due to the Earth's rotation, and is extremely small.
The disturbing torque cannot be greater than the product of the gyro angular momentum and the Earth's rate of rotation, the latter is tiny compared with the gimbal angular velocities or roll rates arising from the balancing loop operation.
Brennan operated his balancing system on a bench continuously for a period of two weeks, primarily to demonstrate its reliability, and did not encounter any free gyro precession of the nature you describe.
The net effect, taking the closed loop behaviour into account, is also likely to be a slight bias on the gimbal deflection, the magnitude of which I shall calculate and include in the article. Gordon Vigurs 09:58, 29 September 2007 (UTC)


So Louis Brennan operated his balancing mechanism on a bench continuously for two weeks and found that the rotation of the Earth did not affect the stability of the vehicle. This seems counterintuitive.

Consider a stationary, gyro stabilised monorail vehicle, sitting in a siding, pointing north south, and its mechanism working. It has a single gyroscope, for simplicity, which spins on a vertical axis. As the Earth turns, the fixed point the gyroscope axis points to moves across the sky, and the gyroscope wants to follow that fixed point, and will take the vehicle with it. There is no roll force, in the sense that a strong side wind imposes a roll force, but the vehicle will roll west by 15 degrees an hour as the Earth rotates.

The stabilising mechanism will detect the roll, and will force the gyroscope to pitch to restore the vehicle to vertical. The gyroscope axis now points to a slightly different part of the sky. But the Earth continues to rotate, and the gyroscope axis will continue to follow that new fixed point, so the stabilising mechanism, must, as far as I can see, continue to force more and more pitch to the gyroscope to keep the vehicle vertical. Eventually the forced pitch will approach 90 degrees, and the gyroscope will no longer keep the vehicle vertical.

If this analysis is incorrect, where is my misunderstanding?

If the stationary monorail vehicle is sitting in siding, but pointing east west, and the vehicle has two gyroscopes, contra rotating, then the vehicle will stay upright indefinitely. The gyroscopes will try to follow a fixed point in the sky, and will try to pitch the vehicle. The vehicle and rail will resist, and will force precessional rolling motions, but in opposite directions, so the vehicle stays upright indefinitely. The gyroscopes are continually forced to point to different parts of the sky.

David Erskine


58.168.40.76 06:30, 1 October 2007 (UTC)

Brennan's testing of his balancing system is a matter of history, not intuition.
The precession which you describe initially causes the vehicle to tilt from the local vertical. As it is an inverted pendulum, it will start to accelerate in roll under its weight, forcing the gyro to precess, imparting a torque to the gimbal. As the gimbal mounting is unstable, it will accelerate away from its initial position, generating a righting moment about the roll axis as it does so, causing the vehicle to return to upright. As the vehicle rolls back to the upright, it generates a gyroscopic torque, returning the gimbal to its central position.
The system parameters needed to ensure that this process is stable are derivable from the coefficients of the characteristic equations governing the motion, presented in the text.
The 15 degrees per hour roll rate, to which you refer, is an impossibility because the weight of the vehicle will cause it to topple, initiating the balancing system response. It is this overturning moment which paradoxically renders the system controllable. Likewise, the unstable gimbal mounting will cause an acceleration of the gimbal from its central position, also initiating the balancing system response.
You describe a real effect qualitatively, and within the limitations of qualitative reasoning, it sounds credible. However, without quantitative estimates of the forces involved, the argument is specious. Quantify the terms 'try to' and 'wants to' in terms of the magnitudes and directions of the torques involved. The gimbal is not free to rotate, as the motion you describe implies.
In particular, the statement that the gyro during free precession will somehow impart an infinite torque to 'bring the vehicle with it' is utterly absurd. The maximum torque which can arise from the Earth's motion is calculated as 0.38Nm for a 10 Tonne vehicle. Your argument implicitly claims that this dominates the motion, when the toppling and actuation torques are of the order of 2500Nm for only 1 degree of gimbal deflection or roll disturbance. There is indeed a tendency for the gyro to move as you describe, but in the presence of a self-correcting feedback control system producing actuation torques four orders of magnitude greater than the disturbance, the result of the tendency is a mere thousandth of a degree residual deflection.
In the process of righting the vehicle, the balancing system also centres the gyro in its gimbal, this takes place simultaneously with cancelling the roll angle, and as the Earth continues to rotate, it continues to correct for the tendency of both gimbal deflection and roll angle to deviate from equilibrium. However, the equilibrium position involves a small steady state torque arising from the Earth's (continuous) rotation. This manifests itself as a net increment in equilibrium roll angle or gimbal angle of the order of one thousandth of a degree.
The motion of the vehicle with the earth is no different in nature to its motion around curved paths on the Earth, the net result is pitch and yaw with respect to inertial space. That the motion arises from the Earth's rotation does not endow it with any special magic. In order to predict motion, we begin with forces and then solve the equations of motion, we do not simply read across from the kinematic solution for the free gyro.
The premise that the gyro will maintain its orientation with inertial space, when it is subjected to restraining torques, is arrant nonsense. A free gyro maintains its orientation with respect to inertial space because there are no moments acting on it, hence its angular momentum remains constant. Applying moments to the gyro changes its angular momentum in analogous manner to a force applied to a body changing its linear momentum. A gyro in a high quality Cardan's suspension would precess as you describe. Actually the gyro maintains its orientation - it is the Earth which rotates. Gordon Vigurs 07:40, 1 October 2007 (UTC)
Your knowledge and understanding of gyroscopes is probably better than the majority of practising engineers, but is far from complete.
In this respect, the situation has not improved much since Schilovsky's days, except that very few modern engineers have the integrity or good grace to admit their ignorance. Few engineering undergraduate courses consider gyroscopes at all, and those that do tend to restrict their consideration to inertial instruments, rather than as a means of actuation. The mention of gyroscopes, bearing in mind their tendency to turn up in reactionless drives, perpetual motion machines and similar absurdites, naturally induces a feeling of unease, which no amount of rational argument, or even working hardware, will dispel.
Of course, relying as it does on basic Newtonian mechanics, the humble gyro is beneath the dignity of the physicist or applied mathematician - except perhaps as an elementary example of the application of Lagrange's formulation. Neither of these disciplines seek to impart the engineer's intuitive grasp of the phenomenon, which is essential for the development of products which actually work. Gordon Vigurs 09:34, 22 October 2007 (UTC)

[edit] Legacy Infrastructure

How seriously does a society take rail travel? If maglev becomes widely accepted, because of the speed, a society would be motivated to resume land forcibly, if need be, assuming adequate compensation. The same applies to fast gyro monorail.


58.168.40.76 08:45, 28 September 2007 (UTC)

Valid comment, but in fiercely democratic, market driven economies such heavy-handed action on the part of the state is likely to be met with concern, if not outright defiance by the populace, with correspondingly short political careers of those who authorise or endorse it.
The freedom of the individual over the power of the state was hard won and is not likely to be surrendered lightly. An approach which accommodates individual rights whilst simultaneously improving surface transport performance must therefore be considered superior to the current meglomania of forcing straight paths through the countryside, no matter who gets in the way, or how much the civil engineering works cost.Gordon Vigurs 10:10, 29 September 2007 (UTC)


If City A and City B want a fast, straight railway, monorail or otherwise, and a small number of landowners refuse to sell, then that small number of landowners are blocking the wishes of a large number of people. Democratic societies are not impressed with such behaviour.

I used the phrase ‘adequate compensation.’ I should have said ‘generous compensation’. Private land developers, faced with landowners reluctant to sell, are prepared to use generous compensation to get people off land, if the company wants the land badly enough.

David Erskine

58.168.40.76 06:28, 1 October 2007 (UTC)

I don't disagree about how people ought to behave. My point is that in the real world they don't behave like that. The point is noted that land acquisition is likely to be an expensive business, and with the odd public enquiry thrown in, likely to be long-winded as well, all of which is avoided by using existing rights of way.Gordon Vigurs 07:54, 1 October 2007 (UTC)


The comment in the initial section that "legacy infrastructure imposes severe limitations on modern train performance" is completely without basis. The statement isn't even correct - if a new high speed line is laid out with a minimum turn radius of 7 km, it is because anything tighter would involve uncomfortable acceleration onboard the train! This is a result of physics. I don't care how many wheels the vehicle has, the faster you go around a curve of a particular radius, the higher the acceleration. You want to turn more quickly? You have to slow down. TGV trainsets can and do make tighter turns than that on "conventional" lines. This is another point: the French TGV, as an example, operates over more than just the high speed lines, it continues out over "conventional" lines at reduced speeds. This was part of the idea right from the start. The argument that a TGV system requires a completely new network is just plain false. The author clearly does not know what s/he is talking about!!!

GreatGreenArkleseizure (talk) 21:51, 11 March 2008 (U

You fail to grasp the fundamental point that a vehicle which banks like an aircraft will not expose the passengers to the lateral forces, which are the principal limitation on conventional trains. Instead, the acceleration acts vertically, a direction in which the human body is considerably more tolerant. This imposes a limit of about 1.2g before the acceleration becomes noticeable, so the monorail radius of turn constraint, based on ride quality, is about 1.5km at 360km/h.
A standard gauge railway vehicle would simply topple on a curve of this radius at this speed, unless impractical amounts of super-elevation were used. Actually, the toppling limit for this speed is some 3.6km, but this would subject passengers to about 0.3g laterally, which is quite unacceptable. At 7km this reduces to 0.15g, which still does not compare favourably with the 0g lateral acceleration of the monorail. If you don't know how to check these figures, I suggest reading Conical pendulum.
I suggest you get your facts right, before reverting to unseemly insults.
If you cannot understand basic dynamics, you are not qualified to remove the references to right of way advantages, which I have consequently re-introduced. 1.5km is less than 7km QED.
The much tighter potential radius of turn increases the options available for choice of routes.

Gordon Vigurs (talk) 10:21, 20 May 2008 (UTC)

[edit] Monorail theme parks

Roller coaster vehicles could be converted to gyro monorail, adding extra novelty to the experience. A wire rope bridge can be included, as done by Louis Brennan. The public would become introduced to the idea of gyro monorail.

At Disneyland Los Angeles, patrons get from one part of the park to another by a slow train which runs round the perimeter of the park. This train could be a gyro monorail vehicle.

58.168.40.76 08:44, 28 September 2007 (UTC)

[edit] Original research

Almost the entire article here is presented as personal conjecture and rebuttal, as embodied in these statements from the lead:

"While these may have been, and probably still remain, minor contributing factors, the only nations with the technology to develop the monorail at the time already had perfectly satisfactory conventional railway networks, which were not due for replacement.
However, at present, when that same legacy infrastructure imposes severe limitations on modern train performance, the case for the monorail as a means of exploiting existing routes, rather than building a complete new network, to accommodate the next generation of high speed train, does not appear quite so weak.
Unlike more obvious means of maintaining balance, such as lateral shifting of the centre of gravity, or the use of reaction wheels, the gyroscopic balancing system is statically stable, so that the control system serves only to impart dynamic stability. The active part of the balancing system is therefore more accurately described as a roll damper."

Weasel words and research synthesis apparently fill the entire article. Every assertion within the article needs to be cited, the reflective/essay-like sections need to be completely removed. That mathematical formulaic section at the end? That either needs to be cited or removed, because it reads like nothing more than original research. • Freechild'sup? 15:30, 18 February 2008 (UTC)

Your comments indicate that a one for one reference to the paragraphs of the references cited at the end is what is required, rather than a distillation of the content. Be my guest, if you have either the time or intellectual capacity for the job.
The style requirements, which appear to be interpreted as 'restrict the article to who what,when and where', do not take precedence over common sense, as is clearly stated in the manual of style. I don't know how you write essays, but they sure as hell aren't in the passive voice illusrated by equations; so the style tag in the math section is nonsense. The fact that you may not understand it does not, in itself, render it invalid. To those who can, it renders the article a more authoritative source, as it explains the behaviour in an objective fashion, which couldn't be further from the personal opinion, of which it is accused. Those who can't are accommodated by the qualitative description of the earlier sections.
In the maths sections of Wikipedia, this guideline is ignored completely, because it is obvious to the meanest intellect, that the subject matter cannot be presented as if it were biography or history. The consequence is that, in stark contrast to the remainder of the encyclopeadia, the Wikipedia maths articles are widely respected as references.
To quote Henri Poincaré: 'facts do not constitute knowledge any more than a pile of bricks constitutes a house'
If I may make a general comment, regarding writing style rather than engineering substance: Nobody is going to read such very long, very wordy comments in an online forum like this. If you want to really convince people, you have to edit yourself way down; otherwise you're wasting your time. Brevity is the soul of wit and the soul of science, and it's certainly the soul of arguments. - DavidWBrooks (talk) 20:38, 20 May 2008 (UTC)
You are of course right. The sound byte rules, presentation is indeed valued over content. Bullshit always beats brains. I would dispute that this is how either argument or science should be conducted. Surely content and valid reasoning have some value? 86.141.4.252 (talk) 07:38, 21 May 2008 (UTC)
Much to the dismay of uber-geeks, presentation matters almost as much as content - if nobody can understand what you're saying (or stay awake because you're long-winded and dull) you won't convince them even if you're Einstein-squared. Wisdom that can't be conveyed to others isn't wisdom, it's navel-gazing. - DavidWBrooks (talk) 14:44, 21 May 2008 (UTC)
I have deleted most of the comment, following your advice. The problem remains that the operation of this particular machine is very difficult to describe in a simple fashion. Most simple explanations I have come across are just plain wrong, and seriously misleading. Perhaps we should delete all the exposition, leaving just the historical section, and content ourselves with recognising that Wikipedia aims to be useless as an engineering reference.Gordon Vigurs (talk) 16:59, 21 May 2008 (UTC)
Popular exposition that is accurate and accessible is very difficult, indeed - many scientists look down their nose at it until they try to do it.
And Wikipedia absolutely does not aim to be an engineering reference. It is designed for the mass audience, most definitely not a reference work by experts. It's true that we have many articles incomprehensible to laymen, particularly in mathematical topics, but that's a flaw, not a feature. (Making complex theoretical math accessible to the general public (e.g., me) is orders or magnitude more difficult than making engineering articles accessible.)- DavidWBrooks (talk) 21:27, 21 May 2008 (UTC)
I have been exposed to enough pretensious, arcane work to fully understand your sentiments. In our atempts to be accurate and accessible, the result can be rather turgid, as we find we have to explain so much more in simple english. The word count goes up, and the sheer mass of text itself becomes repellent. I am aware that this article is already too long, and am open to suggestions as to how to shorten it without discarding the facts.Gordon Vigurs (talk) 05:07, 22 May 2008 (UTC)