Talk:Gyro monorail

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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)


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)


Well, this artice 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)

I like this sentence:[edit]

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? -- 05:44, 20 November 2006 (UTC)

If you insist[edit]

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. -- 03:05, 7 January 2007 (UTC)

Request to 'wikify'[edit]

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)


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? -- 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. -- 12:59, 26 January 2007 (UTC)

Rotation of the Earth[edit]

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 (talkcontribs) 06:44, 21 September 2007 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 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)

Legacy Infrastructure[edit]

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. 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 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)

Anyone who truly studies high speed rail technology will of course be aware of the other ways to counter-act centripetal force beyond simply slowing down - primarily super-elevation and tilting rail vehicles (of which the Gyro Monorail could be considered an extreme example). Several types of tilt systems are in place - active and passive - in order to achieve higher speeds on conventional rail lines, where it is not possible to increase curve radius or apply further super-elevation. The reasons that truly high speed lines require dedicated right of way is related to much more than curvature, although that is an important part. Gradients, axle weights, signaling systems, maintenance standards, road crossings, stations, passing sidings (loops), etc., are also extremely important parts of railway planning that all conspire to require new right of way for the fastest, most efficient high speed railways. In the case of the French TGV, because new right of way was acquired due to all of these factors, it was not necessary to use any tilting technology to counter centripetal forces. This does not discount the need for, and success of, alternative technologies when this right of way is simply not available. Jpp42 (talk) 10:23, 21 July 2008 (UTC)
Thank you for your contribution. There are also favourable arguments in terms of gradient, and the other infrastructure issues to which you refer. The balancing system is actually simpler than most tilting train systems. However the principal reason the monorail will never enter civil passenger service is its inherent instability, which is unlikely to get past the certifying authorities, regardless how compellng the technical argument, particularly when an inherently stable option is available. The CAA/FAA are unlikely ever to approve a stability augmented, directionally unstable airliner, even though the technology is widespread in the military field. Gordon Vigurs (talk) 05:19, 5 August 2008 (UTC)

Monorail theme parks[edit]

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. 08:44, 28 September 2007 (UTC)

Original research[edit]

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? (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 pretentious, arcane work to fully understand your sentiments. In our attempts 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)
I have seen little evidence of improvement of the article from those complaining so vociferously about its alleged defects, and I personally have neither time nor inclination to change what is written. It has been written with a broad audience in mind, which includes those of higher educational achievements, as well as the more general readership, which is adequately accommodated by the earlier non-mathematical sections. The latter parts do indeed read 'like a textbok', but then an encyclopaedia IS a text book. The offending sections are clearly marked as the domain of the nerd, who has as much right to access knowledge as everybody else. There is a lot of difference between appealing to the intelligent layman and bowing down to the lowest common denominator. Wikipedia may be many things, but it is not a comic. Gordon Vigurs (talk) 11:35, 10 July 2009 (UTC)


The mention, in the introduction, that each unit of a monorail train must have a balancing system is no more than a piece of speculation based on intuition, rather than fact. Schilovsky, it is true, proposed monorail trains (including a steam locomotive!), which did not contain a balancing system in every car, but relied on a number of balance cars distributed along the length, and his two-unit monorail contained a single balance car.

However, I am not sure how well he thought things through, because the dynamic analysis of a pair of gyroscopically stabilised vehicles, if coupled together rigidly, yields an unstable combined system. Thus, putting a balancing system in each vehicle would result in catastrophic instability, unless there were zero roll constraint between adjacent cars. In practice, it is unlikely that a gyro train would consist of more than two or three units relying on a single balance car.

This also introduces dynamic interactions between the suspension and the balancing system on bends, which requires careful analysis.

The problem of coupling two gyro-stabilised vehicles might explain why Schilovsky had problems getting twin counter-rotating gyros to work, and why he opted for a single gyro solution. He may simply have failed to couple the gimbals as in the Scherl and Brennan system, and consequently encountered this particular instability. Gordon Vigurs (talk) 07:42, 6 April 2009 (UTC)

Fair enough - I watered it down slightly ("many cars" instead of "all cars"). It's still an obstacle to large-scale adoption. - DavidWBrooks (talk) 10:55, 6 April 2009 (UTC)

Agreed - the rolling stock will be expensive, although not drastically different from conventional high speed rail, particularly if tilting is employed. The dominant cost is the acquisition and maintenance of the permanent way, which by using existing routes and employing a single rail at ground level, plus a reduced requirement to keep the track straight and level should lead to a reduced overall system cost. However, there is not a hope in hell of the technology ever being certified for civil passenger transport, so this is really an academic issue.Gordon Vigurs (talk) 16:12, 6 April 2009 (UTC)

The traditional idea of a locomotive pulling unpowered rolling stock is essentially a throwback to the days of steam traction, when this was the only possible paradigm, because of the fundamental limitations of steam engines. With more modern prime movers, passenger transport in particular has shown an evolution to train sets of two, three or four units, and we should expect future systems to use individually powered units, as is currently used on the Japanese bullet train. The restriction to a few units with a single balancing system is in keeping with the modern trend in passenger railways. Considering the need for balancing systems in each vehicle; this is a characteristic of tilting trains used on conventional track, yet it is not presented as a major disadvantage in that context, even though the combined suspension and tilting system is more complex than an equivalent gyro balancing system. Furthermore, the gyro mass is significantly less than the extra bogie weight needed to run on two rails. Please restrict your comments to facts, rather than intuitive guesswork.Gordon Vigurs (talk) 11:57, 10 July 2009 (UTC)

Maximum spin rate[edit]

Should the maximum spin rate of a gas turbine engine, given in Gyro_monorail#Maximum_spin_rate, really be 400 rpm? This seems rather low to me, particularly when rates an order of magnitude higher than that are readily available from reciprocating engines. If I am being ignorant, please do point out my ignorance!

Moreover, is the term 'peripheral speed' used correctly? I would be glad if someone could define it for me; Googling the term did not seem to help a lot.

Jonabofftalk 23:31, 14 December 2009 (UTC)

This article was largely the work of Gordon Vigurs, as you'll probably suspect from this talk page. He doesn't seem to have been active on wikipedia lately, but hopefully will see your note. Obviously, anybody with knowledge can respond/edit. - DavidWBrooks (talk) 00:08, 15 December 2009 (UTC)

Some genius changed 400m/s to 400rpm. The peripheral speed is the speed of the extremity of the wheel with respect to the centre, hence it is a linear speed. It is indicative of the centrifugal stress in the disc, so exceeding this sort of value with a steel disc may result in the disc bursting under inertial load. The larger the wheel, the slower it must spin to respect this limitation. A 0.2m radius gas turbine spool may spin at up to 20000rpm, but a 1m radius gyro would be limited to less than 4000rpm. Gordon Vigurs (talk) 21:15, 2 January 2010 (UTC)

Two questions on outstanding matters[edit]

First, I was wondering what the start up and close down procedures were. Simplistically, one would expect that with no power the toggling springs would push the flywheels over to the stops, and that simply starting up from that wouldn't work reliably; also, if the stabilising started while the support legs were down, that might lift the vehicle over to one or the other side - yet, if the legs were brought up first, the vehicle would topple in the usual way. Similar issues come up in reverse when closing down. So there has to be something going on that isn't covered in the article, or I'm missing something blindingly obvious.

Perhaps I should add how I would have handled it, although I have no idea if it's the best way or if it's how the actual designers handled it. It involves two things: having two support legs (one on each side, probably ending with small wheels to allow shunting) that don't lower all the way to the ground but only to a few inches above it; and, locking/unlocking the gyros with the legs down (say, with a pin going onto the servo-driven rack). Locking the gyros would allow a gentle topple a short way to one side, after which the system could be powered down. Unlocking them (once they were spinning!) would start the vehicle rocking on the bogie suspension, up to the point where the support leg unloaded, after which it would right itself and the support legs could be raised. PMLawrence (talk) 12:31, 10 March 2010 (UTC)
No problem. The gyro stabiliser has to be an active system doing work because keeping the vehicle upright means lifting the centre of gravity a small amount. At start, the vehicle is standing on legs at a slight tilt, and once the gyro is at speed, forced precession will make the vehicle vertical. At stop, the gyros keep the vehicle upright, the legs are deployed, and as the rotors lose momentum, the vehicle will slowly tilt a few degrees from vertical until supported by a leg.
The vehicle interprets start and stop as a deviation from vertical and corrects, something it does all the time while working. David Erskine (talk) 11:17, 7 May 2010 (UTC)

Second, after the narrow window of opportunity for pre-1914 military uses closed, the technology looks like "a solution in search of a problem". I started musing idly about possible areas it could benefit. I think I may have found one: helicopter stability (a lesser one would be a "monomaran" - a narrow, single hulled yet stable vessel, possibly with sails or possibly a seaworthy monitor (warship)). For various reasons I won't go into, a conventional helicopter is inherently unstable (curiously enough, it would be stable if the rotor were underneath - but that would interfere with landing and taking off). Much work has been done to reduce the instability to the point where pilots could manage it, and to train the pilots - obviously successfully. Nevertheless, this adds to overall expense, what with the additional hardware, added training, and so on - and it gets trickier with UAVs, where pilots' reflexes are less in the loop. It struck me that a set of two perpendicular Brennan-style stabilisers (allowing freedom of yaw) could make a conventional helicopter inherently stable, with the added weight being offset by not needing things like the Bell or Hiller systems, that also have to be integrated with the transmission and main rotor and control systems - though a pilot trained to cope with the instability might need retraining if it turned out his modified reflexes caused Pilot induced oscillation. (Of course, the same modern avionics that made UAVs practical might mean that they can create effective stability and that the problem is no longer an issue.) Anyway, I was wondering if any work had been done applying this article's systems to helicopters, and if so can anyone supply suitably referenced material about it here? PMLawrence (talk) 13:58, 9 March 2010 (UTC)

Just a reminder - wikipedia doesn't exist as a forum to discuss issues. This talk page should be used for discussing the ARTICLE, not people's ideas about the topic. Please take this kind of conversation elsewhere; wikipedia is enormous enough, as it is! - DavidWBrooks (talk) 12:58, 10 March 2010 (UTC)
Those two questions are relevant to this article: just how did the original systems start up and close down? and, was this technology ever used in other application areas (and, if so, can it be linked and referenced etc.)? But I can see how my wording might have misled you into thinking that I was just musing generally, because it was so diffuse. Avoiding that was why at first I didn't put in how I myself thought start up/close down could be handled. I only put it in as an afterthought once I saw that my asking the question on its own might make it look as though I didn't understand how it could be done and was asking for that. But I gave the second question too much of that sort of background to begin with. Even so, the core questions are relevant. PMLawrence (talk) 14:41, 11 March 2010 (UTC)

The monomaran is an interesting idea, but may also be a solution looking for a problem. I have heard of the Comte de Savoie, an ocean liner betwen the wars, I think. Conventional, except that it had three gyro stabilisers to keep the ride smooth. Later ships used stabilising fins. David Erskine (talk) 11:23, 7 May 2010 (UTC)
The ship is Conte di Savoia, & there is a Wikipedia entry. Perhaps it should be mentioned in this article becuase of its gyro stabilisers. DavidJErskine (talk) 02:11, 11 May 2010 (UTC)
In response to the outstanding questions, I must admit ignorance. There are several potential schemes which could work, but which ones Brennan, Scherl or Schilovski actually used, I haven't a clue. The Royal Aeronautical Society paper; 'Brennan, His Helicopter and Other Inventions' contains a vague reference to his car which apparently lowered and retracted outrigger wheels automatically. If you find out how they did it, please include it in the article.
Contrary to the accusation of 'original work' I have restricted my description to the actual modus operandi of the Brennan and Schilovski systems. Many other solutions are possible, and description of them would indeed have constituted 'original research'. The technical section, as is clearly marked, is not accessible to everybody, but constitutes a concise description of the function of existing systems. However, it does not present systems designed in the light of modern control theory.
Regarding gyro-stabilisation of ships, a number of designs were proposed associated with names Schlick and Sperry, as well as Schilovski. These were mainly to provide roll damping on a statically stable ship. I may well be wrong, but I do not know of any case of a statically unstable ship being stabilised with gyros. Gordon Vigurs (talk) 09:47, 18 June 2011 (UTC)

Original research[edit]

This article has been tagged as "original research" for three years, and no references have been added. I'm going to start removing OR material, starting with the long section on "effect of Earth's rotation" unless there can be some sort of background supporting it. We're not a place for ruminations, no matter how intelligent or mathematical. Publish it somehwere first, then link to it - that's how wikipeida works. - DavidWBrooks (talk) 15:06, 1 June 2011 (UTC)

Fine by me. However, I am confused. Rephrasing and summarising information from elsewhere, or presenting the same information in concise mathematical form is 'original research', whilst verbatum copying infringes copyright. Little wonder Wikipedia is viewed as a joke by serious researchers. Gordon Vigurs (talk) 08:19, 24 June 2011 (UTC)
Without references, it's not clear that it's "rehphrasing and sumamrising" or just a free-flowing essay by a home theorist. References are the key. And wikipedia is not designed for serious researchers, any more that World Book is. If anybody is doing serious research here, they're something of a joke themselves. - DavidWBrooks (talk) 10:53, 24 June 2011 (UTC)
Having said that, I've never actually gotten around to my threatened cuts. Judging from the lack of comments here, it gets so little readership that I find it hard to take the time, shame on me. - DavidWBrooks (talk) 10:55, 24 June 2011 (UTC)
Firstly, there are references covering all the material presented, which you seem to have overlooked. Secondly, am I to understand that the popular view is correct, that Wikipedia is not only nonsense, but that it takes pride in its utter unreliability? By all means cut as you please. Gordon Vigurs (talk) 17:17, 25 June 2011 (UTC)
I know it's fun to get huffy and self-righteous, but it doesn't accomplish much. Consider, if you will, the long section titled "Side loads". It's completely wrong, incorrectly stated and misleading. No it's not, you insist. How do I, or anybody else, know whether it's correct? We can't: it has no references. No footnotes. There is absolutely no way to check any of those statments within the structure established by wikipedia. It might as well be(and I suspect it is) your own thoughts on the matter, nothing more nor less. That's what I mean by lack of references, not a list of books at the end. - DavidWBrooks (talk) 19:03, 25 June 2011 (UTC)
Are you serious? I have answered this criticism elsewhere on this talk page, which you do not apear to have read either. To what level of remedial mathematics must I refer before I reach the level of the assumed readership? Can I assume for example that I needn't have a reference for 1+1=2? The section to which you refer is valid because it is no more than elementary statics. If the readership really is that dumb, I would concede a reference to a Wikipedia article on 'static equilibrium' might be appropriate. I agree the section on 'effect of Earth's rotation' should go completely, as the issue is addressed in these talk pages. To dumb down to such an extreme level is, I admit, beyond my skills. The subject matter is not the easiest to present, even to to an erudite audience. Either the article will be too long for the readership's attention span, or so trite as to be worthless. I might as well claim the thing works by magic.
You can verify the content be reading the cited references (if your education and/or intelligence is not up to the task of following the exposition, which is deliberately self-contained). If you can't be bothered, don't expect me to apply myself to your whimsical wishes. I repeat, I have responded to this criticism above at some length. Your personal style preferences are not those of Wikipedia. A list of book titles and articles does indeed constitute 'references'. Your criticism is factually incorrect. As far as your suspicions are concerned, I should advise you to keep them to yourself. I need something more substantial than people's uneasy feelings to motivate me to modify what I have written. You clearly have no interest in the subject matter, yet seek to remove material which interests those who do. In three years, nobody else has found lack of references to be a weakness of the article. Stick to history or biography, where your comments are relevant. Gordon Vigurs (talk) 07:55, 26 June 2011 (UTC)
"Dumb down" is a phrase often used by people who don't want to take the time, or don't have the ability, to explain their thinking - often out of fear that such explanation will reveal the holes in their argument. The use of that phrase is, I have found, often a red flag that you're dealing with flawed material.
The point, one last time, is that a lack of footnoted references raises suspicions like mine. If you really think this article is important, you'd take the time to back it up in the format that wikipedia uses - this is wikipeda, remember, not a technical journal. Sneering isn't a very good supporting argument. - DavidWBrooks (talk) 11:40, 26 June 2011 (UTC)
Perhaps you'd lke to check [[1]] - a discussion about footnotes and referenceds in wikipedia, and how it differs from practices in technical and research journals. I suspect this is the basis of our disagreement. - DavidWBrooks (talk) 12:05, 26 June 2011 (UTC)
Whether the article is worth bothering about is up to the readership to decide. I am totally indifferent; you can delete the whole thing as far as I am concerned, if you think it will improve Wikipedia. I have neither the time nor inclination to allocate any more time to it. If you think it so important to have line by line references to the cited material, I repeat, be my guest. I merely initiated this article; it is up to other wikipedians to take over where my talents end. As you so frequently point out, communicating with the intellectually lazy is not my strongest point. The article is written for a wide audience in that the material is presented at more than one level, so that it is at least possible to include the non-trivial in with the superficial. If you think it resembles a technical paper in style, I can only conclude you must have very limited experience of professional journals.
I have tolerated your implicit insults for quite long enough, I think it is time for me to finish with Wikipedia.Gordon Vigurs (talk) 07:57, 27 June 2011 (UTC)
Sorry you feel that way. - DavidWBrooks (talk) 10:45, 27 June 2011 (UTC)
A very diminished article, much useful information has been lost. Got to say I am surprised at the need for references for the (removed) mathematics as it was only an application of well understood classical dynamics - not an exposition of any new mathematics. Same applies for the whole gyro stabilisation thing - there is no new physics, just a clever application. — Preceding unsigned comment added by Srwyidg (talkcontribs) 12:30, 11 January 2012 (UTC)

Counterrotating gyros != no gyros at all?[edit]

Wouldn't two counterrotating gyros result in zero net-force being applied to the vehicle since the forces of the two gyros are exact opposite, canceling out each other? --TiagoTiago (talk) 02:03, 27 May 2012 (UTC)

Refer to Side Loads in Article, para 5. The two contra rotating gyros are on separate axes and forced precession in opposite directions. DavidJErskine (talk) 14:03, 28 August 2012 (UTC)

Acknowledging Gordon Vigurs[edit]

Sorry to hear that Gordon Vigurs has lost interest in his article. Without him there might not have been an article. I have learned from both the article and the conversations with him on the Talk page. DavidJErskine (talk) 07:45, 30 August 2012 (UTC)

Assessment comment[edit]

The comment(s) below were originally left at Talk:Gyro monorail/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

Close to GA quality, needs inline citations. Slambo (Speak) 14:00, 13 December 2006 (UTC)

Last edited at 14:00, 13 December 2006 (UTC). Substituted at 16:54, 29 April 2016 (UTC)